kalirion: Didn't Bioshock let you pause the game while you go into weapon selection menu? I don't think a twitch-based "all action all the time" shooter can get away with that.
I'm actually playing Duke 3D right now, and even with the M+K controls it's a pain selecting weapons mapped to 7-0 keys.
First of all, consider playing with eDuke32 if you aren't already. Secondly, remap your keys!
Try making your weapon switch keys 1, 2, 3, 4, F, V, C, X, Z, G, use Q and E to go between inventory items (and middle mouse to use them), and use R for the boot. You'll be able to keep your hand in the WSAD area for everything but quick inventory buttons. Try to put a quick button for the jetpack nearby (like ALT or B), and possibly the health pack as well.
This should make your gaming experience a lot more fun. I never had too much trouble balancing the 10+ weapon systems in first-person shooters on consoles (...this was back when having a gaming quality computer of your own, as a kid, was out of the question. I can still play Doom very well on an Xbox, but I'd rather play on PC), but apparently today's generation
does.
Damn kids, I miss my questionably scattered and often overpowered power-ups, arsenals, 2D sprites, colored keys, genius non-linear level designs (and sometimes hub worlds, like Hexen! <3), and awesome music. ;_;