I'm pretty opinionated when it comes to talented guitarist so I'd probably go write a book if I read through all the posts...
I just have to say this... your comment on "nu metal" not having solos and such, it's probabably because KoRn started the nu metal revolution and they are seriously not talented musicians. Many guitarists and musicians could relate to them and liked their simple music so they copied them or did variatians of their music. The only solos they have are crappy wah solos which is pretty much jus using a wah pedal and stretching some strings
It's not that solos arent around anymore in in the 90s/00s, it's that the mainstream or popular music dont have many solos, with the exception of a few bands. I listen to a lot of underground, well not really underground but nothing most people have heard of, and there are tons of solos that're very memorible. I suggest listening to
Nevermore,
Arch Enemy and
Soilwork (especially soilwork's song Structure Divine, my favorite solo ever). Also
Meshuggah has some pretty trippy, experimental solos (not on their new album but on Destroy, Erase, Improve & Chaosphere there are some pretty kick ass ones).
Harry, I know some solos may be rediculously thrown in so the crowd goes, "WHOOOOO!! YOU GUYS ROCK! (holds up fists)." But the guitarists who truly know how to make it work, can make a soulful part that overshadows the rest of the song. On the Kurt Cobain subject, I really don't think Cobain is a talented guitarist. He's a good song writer and has REALLY good guitar parts, but they just arent very special. Smells Like Teen Spirit consits of 2 notes during the verse and a lame barre chord chorus like most of their songs. I'm not saying this is particularly bad by all means, but isnt for me anymore.
But it's really a shame that solos aren't as popular anymore

Metallica's old work like Ride The Lightening and Master of Puppets amazed me when I started learning to play guitar. And Kerry King rules