I play slash solos, jimmy page solos and improvise alot to jimi hendrix. Since FFAF came out a couple of year ago ive learned lots of their songs and technically its sorted me out. Id recomend them to all guitarists who arent particualrly into the soul-less lack of passionate music like vai and satriani. Theyre excelletn too.
But more back to teh topic. November Rain is a superb song to learn. Its got 2 immense solos in Am, before the key change to Cm (i think) where thres a killer solo there too. The rest of the song it perfect for really minor chilled out improvisation.
To any new guitarists Id recomend you improvise equally if not more than you learn other people's solos. Its important to make your own style, and realise what YOU like to play. Learn fills and licks from lots of gutiarists, but dont steal them, make your own ones up. and ENJOY IT!