Ack! Staffan beat me to it. Bargle, indeed, and not to forget the one and only Baron Ludwig von Hendriks! Both have the facial hair and attitude of classic villains. Twirl those moustaches and cackle one time, aight!
Other also-rans and favourites:
Lord Soth (before he got ruined by Ravenloft and pot plants)
Halaster (before he got ruined by the novels)
The Egg of Coot (for being mysterious, wacky and threatening)
The Witch-King of Vaasa (high-powered villainy is him)
Larloch (for being so passive and so untapped - stat block villainy)
Gargantua (for bothering to produce big monsters just because)
The Queen of Air and Darkness (forget the drow and Lolth, the real unseelie are where it's at)
Bane, on the other hand, is the Real Ultimate Evil. Not only will he enslave your kids, subvert your government, and dominate your free will, he'll look damn good while he does it. That man's got STYLE.
Pull the other one! Bane is waaay overrated and has anything
but class, IMO - I think it must be his kewl name that pulls the wool over people's eyes. Even Cyric has more class than Bane, by now, reading his own Cyrinishad and going insane as a result...
At least Bhaal was a go-getter and had
focus....he almost did in the Moonshaes and was a very good sport at making a comeback after the Time of Troubles (if you consider the Baldur's Gate CRPGs canon).