I've been playing a bit of the original, plus a bit of Carmageddon 2 today - finally got them working properly on W7 64-bit!
For both, you'll want the
nGlide wrapper.
Run nGlide Configuration and set your settings as appropriate, I'm setting it to resolution of 1920x1080, aspect ratio of 4:3 (this retains the original aspect ratio of the picture), VSync on, and the 3dfx splash screen to On (just to confirm that it's working correctly!)
For Carmageddon, you'll also want DosBox with support for Glide - I'm using
Cosmic Dan's tweaked version of DosBox pre0.74 and am launching it with
D-Fend Reloaded
For Carmageddon 2, again using nGlide, and selecting the Glide version when running (rather than Direct3D) - but, importantly, I've installed the
Super Patch V2 - and after setting Compatibility Mode on carma2_hw.exe to Windows 98/Me mode - you can run Carma2.exe to set the initial setup, but after that, run Carma2_hw.exe to launch straight in.
I've got almost 100 games in Steam, but in the last few months I've hardly been able to sit down with any of them for more than an hour before getting bored - I've clocked up about 6 hours between both of these in pure gameplay just today!
Oh yeah, and forcing AA on the executables gives you even better graphics too!