use voodoo3 , since v4 is buggy (WAY BUGGY) and v5 has issues with many games atm (like joyride,earth2140,wipeout and so on...)
v3 offers u best compability.
i also must add that even with v5 using v3 u get theese issues .
do like me, have 1 v3000 and 1 v5500 ... swap em around if u want something special to work.
anyway i must also add that both v4 and v5 is faster than v3 , but its not much but it does show in games like quake 1 and 2 and freespace etc. (heretic 2 wont show much diff tough...)
so be smart, get a v3...and a v5 if the price is right.
cheers