It seems that a boatload of celebrities, whether yesterday’s star or today’s heartthrob, have embraced the leanings of twenty-first century pop culture and started a blog.

What’s exceptional about these online writings by the famous is that they, like all good blogs, run the gamut of subject matter. Some are diaries or journals, others support a cause, while still others offer up a new mode of artistic expression or a way to reach out to fans.

We’ve carefully mined the trove of celebrity blogs on the Web to bring you the most popular, the most profound, the most inspiring, or simply the most bizarre. In other words, here are the best celebrity blogs you’ll find today.

Rosie O’Donnell
English majors and Walt Whitman die-hards might experience a migraine when choking through O’Donnell’s attempts at poetic profundity, but this actress and comedian wins big points for her innovative and interactive blog, a forum she updates virtually daily and sincerely. Webcam responses to fan e-mails are the norm, in addition to a good dose of zesty humor in almost every post. She does write, too, even if some of it is painful. Whatever you do, just don’t expect her not to diss ‘The View‘ every now and again.

Valerie Bertinelli
One Day at a Time’s Valerie Bertinelli wins the prize for Blog-that-Carries-the-Most-Weight. Okay, tongue-in-cheek humor aside, Bertinelli’s online journal chronicles her quest to lose forty pounds, Jenny-Craig-style. Readers will appreciate Bertinelli’s candid approach and can-do attitude in facing a problem with which many Americans struggle.

Jenna Fischer
Just like her sweet, mischievous character on NBC’s ‘The Office,’ Jenna Fischer’s online persona is unassuming and quite lovable. Fischer’s MySpace blog is so popular, it’s up for the Blogger’s Choice Awards’ Best Blog of All Time. We love it because its modesty truly evokes an Everyman…eh, Everywoman flavor. Read up on her onscreen alter ego, Pam Beesely, or real-life anecdotes from the life of an earnest Hollywood starlet (Fischer gets nervous around stars, too). Just don’t expect to find any hint of when her character might ditch her caveman fiance for a certain someone in the Office…

Lily Allen
File this blog under “Love/Hate Relationship,” with the former winning out for detail and style. While the singer’s sometimes “poor me” celebrity whining occasionally gets the best of her otherwise honest and witty entries, she gets points for telling her readers everything from the scoop on other celebs to outlining her political proclivities. If that’s not enough, maybe you can just share a good cry with Allen, care of her ludicrous I’m “a bit chubby” post last May. The last entry was December 21, 2007, and we’re not expecting too much in the next few days, given the unfortunate and tragic miscarriage that Allen experienced just recently.

Gilbert Arenas
Gilbert Arenas, a gregarious and loquacious one-man quote machine, is the star player of the NBA’s Washington Wizards. In his spare time, he also pens a funny, hold-nothing-back blog for the league. His blog, Agent Zero: The Blog File, is the source for fans looking for insight into the mind of a superstar athlete, a personal journal that depicts what NBA life is really like (not every game gets them going like the playoffs do) and what the ballers truly think about other players (see “Stay in the West, Kobe”) and how the cold business reality of professional basketball influences their attitudes and actions (see “Clearing Up My Contract”). If you haven’t heard of Arenas, get ready for a lesson in Gilbertology, the study of all things quotable and outrageous.

Al Roker
Just as sure as he’ll happily tell you the forecast each day for NBC’s ‘The Today Show,’ you can count on Al Roker to have a goofy, jovial Web log. Al’s Journal also wins the prize for most the endearing blogger cartoons bordering a Web page — that is, if you like cute little renditions of Al in a helicopter decorating the page. Read up on the producer and author’s adventures on the popular morning show while scrolling through the numerous accompanying photos that include Al as Grandpa Munster on Halloween. And we gotta admit, it gives us the warm fuzzies each time he signs off a post with “Sunny Skies, Al Roker.”

Zach Braff
Braff owes his blogger street cred to roles in the surprisingly good film ‘Garden State’ and TV’s ‘Scrubs.’ The hilarious and irreverent actor entertains topics silly or solemn – usually the former – and pulls it off so that we cheer him on like he’s the neighborhood kid we watched grow up and make it big. Braff is such a nice guy, his inner poet entreats us to such tidbits as “Be kind, rewind” and “Don’t cut lines/Don’t do lines” as he signs off from his most recent post.

Allison Mack
This actress is super-friendly and a true do-gooder, just like her onscreen character’s friend Clark on CW’s ‘Smallville.’ Mack’s blog is a great combination of the interactive and the inspired, as she invites her readers to complete artistic assignments that would do any flower child proud. The latest assignment for “Allison’s Art: 101,” for example, is to draw a self-portrait with one continuous pencil stroke – no cheating! Self-actualization is also a big theme in Allison’s musings, and she continually seeks a higher purpose with endeavors such as starting Juicy Peach, a grant foundation for struggling artists. Check this blog out if you’re the finger-painting type.

Will Wheaton
You might remember him as Wesley Crusher from ‘Star Trek: The Next Generation,’ but this ruminative fan icon might be more popular today for his much-lauded blog. Now an author, Wheaton touches on subjects including Trekkie fandom, love, musical genius, pop culture and the struggle to do what he loves (acting, writing). And we’re guessing that Wheaton is giving some serious advice against the hardships people face pursuing a career as a detective with the self-penned proverb under his masthead that reads, “Don’t be a dick!”

Mia Farrow
On a more serious note, Mia Farrow’s blog is an example of conscience in action. Using her celebrity status to draw attention to horrifying tragedies and injustices that are occurring in place like Darfur, Farrow leaves the preening narcissism of most blogs by the wayside. Twenty-first century advocacy and humanitarian efforts, we imagine, will find a solid example to follow in this dedicated woman’s online writing.

Moby
Moby, the bald, ultra-hip DJ-extraordinaire, delivers big time in his foray into the blogging universe. Music, politics, Budweiser’s new clam-and-tomato-juice beer – nothing is really off limits with him. What’s more, he updates his online journal almost everyday, replete with opinions galore and an ee cummings-esque disdain for capitalization – the guy refuses to capitalize names and insists on typing the letter “i” the lazy, text-message-in-a-hurry way. He even reveals which political candidate seems most suited to “feeling your pain” if your goldfish dies, and it’s not who you think it is…