Definitely skip the V3 and go with a GF2 MX AGP.
I upgraded my K6-2+ 450@600 from a V3 3K to a GF2 MX and WOW!!!
Since you are still CPU limited, the MX card runs the same at 800x600x16 as it does at 1024x768x32, so that alone should be a good enough reason, as the V3 couldn't do 32bit if it wanted to. Some games (like Links 2001 and Myst III), now require a 32bit capable 3d card, and it sucks if you want to use one of those games, only to find that the V3 is not compatable with it. Even though performance is CPU limited, I saw a good 20% boost in performance in nearly every game, and if the game supported hardware T&L, the boost was much more. With modern games like Nascar Racing 4, am now able to run with graphics turned up half way at 1024x768x32, instead of nearly all graphics off at 800x600x16. Than of course there is the little thing that 3dfx is gone, and nVidia is not. Last off, if or when you upgrade to a higher end CPU, the MX will give much more performance, and will be fully usable, while the V3 will still be a 16 bit V3.
Of course if I still had the V3 and wanted to find someone to buy it while it still had a slight amount of value left, I would say that IS the card to get. Luckily, I found a ****** buyer a couple months ago, and got $50 for the Full Retail version in original box, with all software, games, and TV out. Took me 3 months find someone that could still use a decent 16bit card, and the Links 2001 32bit incompatabilty actually cost me a sale.