This is a tough one. The guitar solo was one of many ingenious lovely things that died in the nineties. Conspicuous musicianship sounded archly reactionary after the electronic incursions of the previous decade. Cue the Britpop nadir. (But see below for some articles for the defence!)
For me though, one possibly underrated figure is Ira Kaplan of Yo La Tengo:
[from 2:10, and again at about 3:10]
"If I was Johnny Carson I'd say that was a wacky wacky guitar solo", says the voice of authority that is John McEnroe (?!). No wonder his show got canceled.
Clearly, we're into avant noise territory here, so it's often more a case of extended scene-stealing jammage than of solos per se. As in this:
[starts to get particularly good just before 6:00]
Nice shredding action here [from 3:12]:
Wonderfully wayward stuff in this [from 1:43]:
This was released in Feb 2000 but has great stuff all the way through so I'm gonna slap it down anyway:
Exultant lilting orientalism at the end of this [from 2:45]
Okay so here's where it gets parlous.
I'm fairly sure you can get down with this moment of visionary lo-fi clarity, particularly as it's buried on an album by an otherwise deeply noxious band:
I like how early in the song this is. Clearly a guitarist's first "proper" choon. As in: I've just written a verse and a sort-of chorus; what now? SOLO!
I also love this [from 2:08]
Some very winning (pre-Darkness-therefore-justifiable) ironic metallica. And I like that it's Lauren Laverne's brother who plays it, a nice example of sibling harmony to set beside more ambivalent contemporary cases.
And .... I might never live this down, but finally I'd like to put in a heartfelt plea for the following, partly because it was one of the first things I ever learned to play in 1996 as a 12 yr old nipper, but also because it's FUCKING SWEET!
[a short incendiary burst around 2:30]
Now there's a transgressive taste-move for you.
I could unleash more Britpop heresies but perhaps best to leave it there for now.