rnp, vintechx73, api, studio projects, rme. i think that any decent preamp is workable. i also think that almost everything else in the equation is way more important. in order of importance for me would be:
1.good player
2.good amp
3.good cab
4.good space for the rig
5.good mic postioning
6.good mic
7.good pick ups
8.then i guess it would be mic pre next
you pretty much need everything in place to get a killer recording, if you are missing even one, it will just be ok. weve all heard it a million times, rarely does it ALL come together. ive gotten better sounds with cheap mic pres and everything else in place, but not vice versa. that being said, if everything else is in place, then a really nice pre will do it justice imho.