I'll probably take a look at the show because of Fillion, mainly because of his history with Whedon. (He was also a recurring very bad guy in Whedon's Buffy.) Unfortunately the previews make it seem like the show is going to be a lot of sledgehammer wiseass cop stuff of the Bones kind, which I've seen more than enough of. But we'll see.

It's too bad Whedon didn't put Fillion in Dollhouse. He would have fit in perfectly. Oh well.

I agree with you that Nathan Fillion is a natural born actor - he's sharp and charismatic - for that reason I tuned into Castle last night. I think Nathan will shine in this role - because he just shines. I don't think Castle has the ability to be a great show (unfortunately, I thought the writing was weak and none of the other supporting characters captured my attention) and if ABC's track record with cop shows hold...it's doomed before it even really begins. Which is unfortunate, because I'd love to see Nathan on tv in a role that would last more than a few episodes. He needs to have a director/writer like Whedon behind him.

Not that keen on Castle (the show itself), but a big Nathan Fillion fan. Hope it does well for his sake.

Castle is the best show on TV, one show and you're hooked!

I think that since this show's writing has greatly improved and the plots have certainly thickened, it would be worth your re-visiting Castle. I wasn't drawn in by the first few episodes so blew it off despite Fillion's considerable charms. But I caught the season 3 finale and was fascinated, then watched a marathon and got hooked in. Since I haven't watched many other crime series (the last regularly was Monk, and before that the X Files) ... I don't know whether the crimes are relatively original or exceptional. Flirtation is handled expertly and has matured into (so far) unrequited love; there are also some intriguing story arcs of unsolved crimes that come back to haunt the team. The ensemble cast has hit its stride, too, and surprisingly (to me) a major character was killed off. Added fun: occasionally there are nods to the actors' cult status or relationships to other productions (i.e. Firefly); it's fun to spot the in-jokes.
The only real downside: Sometimes the mix of screwball comedy and drama is uneasy, where there are sad/serious moments followed too soon by humor; and there are a couple of real dud episodes; but overall it's a very good show.

[It has gotten stronger as it's developed, agreed -- and sometimes makes the Best Bets for Monday, depending on the competition. So we're on the same page here. - DB]