No, Ep2 won't work with 64, and it won't work well with 128 either.
Strange, I can play it with my 2,5 year old 9550 128 MB with almost everything on high (shadows on medium of course), with HDR on, and in 800x600 at an average 45-50 fps, 1024x768 at average 35 fps. Sure, you can't say "OMFG120FPSLOL" but it's certainly not lagging. And if you're not in posession of a big-ass 19" monitor, 1024x768 is quite nice. As for the 64 MB Geforce 4 Ti...the raw power of that card is even greater, than the power of my 9550. (old example, but true: 3DMark2001 at 1024x768 - Radeon 9550: ~7200 points, Geforce Ti 4200: ~10000 points)
I don't know about compatibility issues, or how much ep2 supports Dx8 cards, but if it does, it should run at a decent frame rate in 800x600. The new, optimized source engine can run at a decent frame rate even on older cards (thank you Valve) and I'm sick of those people, who urge others to buy the latest goddamned harware.
Yep, if you absolutely need to play every game that comes out, and play them above 1024x768 with all flashy effects turned on, and if you're rich / obsessed / retarded enough to buy a new video card every year (preferably half year), do it.
EDIT: Sorry for the harsh response, but it's just incredible how much the gaming industry tries to contol the gamers.