The only problem with VMWare is that its compatibility isn't as good as VirtualPC. VMWare's emulated devices are purely proprietary and thus go undetected by any DOS apps that look for specific hardware. VMWare's only advantage is that it's faster -- which doesn't count for much if you can't play much on it. :-)
VirtualPC emulates an actual SoundBlaster 16 for audio and a VESA 2.0-compatible S3 Trio32/64 (732/764) for video, so for playing old DOS games it's a better choice. Plus, you can install a neat little patch that allows complete drag-and-drop from the host OS to the emulated OS, making installing old games a snap. :-)
However, you should have at least a 2.4GHz P4 or 2GHz Athlon to get something approaching proper speed without glitchy sound. I've played a few Build-engine games (Duke3D, Redneck Rampage, etc.) on my 1.53Ghz Athlon XP under VirtualPC 5.1 (the last Connectix version) and the speed isn't the greatest and the sound stutters pretty seriously. I've yet to get Microsoft's updated version, but from what I read of their changes, they haven't really done much for compatibility or speed optimisation yet. (Wait ... "speed optimisation" and "microsoft" don't belong in the same sentence anyway...) Then again, VirtualPC was and still is partially developed by
Aaron Giles (of MAME fame), so maybe in this case, they do. :-)
As for Bochs -- isn't that only for Linux?