i have to say the best solo is from seize the day by avenged sevenfold it has a really smooth flow and solos are not about how fast you can play but it is about technique
Maggot Brain by Funadelic this is definitely my favorite solo, the entire song is and instrumental, and yes its by a funk band but listen AT LEAST to around 4:30, thou the lead guitar only starts at 0:45. trust me u will not be disappointed
I don't think it counts as a solo, but the {url=http://www.youtube.com/watch?v=-l3_gwIOTGI]opening of Loser at the Reading music festival in '03 is probably one of the best guitar parts ever. I honestly had to go lay down for about 8 minutes after hearing this for the first time.
This is an instrumental, but Nosferatu by Coroner. I was just listening to it and it's awesome. Coroner has even been called "The Rush of thrash metal."
I think you all should hear this. I can't even Imagine why this is not one of your first thought when you think about guitar solos. Really. Innuendo. Queen.