It really depends on what you use it for. Word processing sucks, but outputting VCD's and DVD's - oh, boy!
Another excellent output - Winamp visual plug-ins!
Games are so-so, there's a noticeable difference between OpenGL games and others (Unreal vs. Quake 3 vs. Soldier of Fortune).
Overall, still, if you have a good TV, you'll be able to get some decent picture. I don't know about Voodoo3, but the thing is that TV resolution must be 800x600, which cuts performance anyway.