Depends on my mood and the situation ... I fly as many as 4 or 5 different planes in any one night and like 'em all in their own ways. One of the advantages of playing these games so long is that switching planes doesn't affect me too much.
Mosi if we're doing base capture and after 30 minutes the damn city still ain't completely down - about the fastest way to get a pile of ord and cannons someplace.
Currently I use the Spit IX for general patrol work - but my style is e-fighting, so you won't see me caught in a flat turn unless its time for the coup de grace. Otherwise I patrol in a P51D if it looks like I'll have to go a couple sectors to find stuff.
109G-10 for killing high alt bombers. Duh.
Sturmi for killing GV's and last ditch base defense.
La-5 or Hurri IIC for base defense, depending on how far from base the intercept is. La-5 is nice because you can get out of trouble as fast as you can get in it and folks pay more attention to La-7's.
F4U-1 or F6F for work from CV's ... depending on if we need ord or CAP. FM2 once in a while for chuckles if we're offshore an enemy base.
Fw190A-5 (2 cannon only) or D-9 for maintaining CAP over enemy bases - which one depends on my mood. The A-5 is more fun, but on nights when the Warp Gods are against me and I can't hit the broad side of a dweeb I take the D9 so I can get home at least. The roll rate and cannon ammo of the 190 is hard to beat.