I agree about Taylor's performance this year being excellent but I wouldn't put him up in the Defensive MVP race. I know it's kind of unfair but I feel the Defensive MVP will be someone who is able to make their team win.
Unfortunately, with Miami's record (Unless it gets drastically better, which I hope it does), they're not winning enough to have any league MVPs. I know Jason Taylor has helped the Phins tremendously in the last couple of wins (And in some losses which were absolutely not his fault) but it's pretty much guaranteed to go to a player who forms part of the defence of a team which wins lots of games.
At the moment, I think Tommie Harris seems to be the front runner for NFL Defensive MVP (He gets a lot of press acclaim) but that could all change over the rest of the season. Hopefully Miami will get on a streak and that'll help Taylor's case. Actually, no harm to him, but I'm a lot more worried about Miami winning games than any of the players making it to the Pro Bowl or getting MVP awards. Sorry about wittering a bit there.