If you like Nirvana, than you must have the "Alice in Chains" unplugged. Raw & gutsy & awesome.
There's also a sort-off semi-acoustic, very "ambiental" Pearl Jam (audio only, double CD), not from the MTV Unplugged branded series though, but still a great and very accurate recording of a great live event - "Benaroya Hall (Oct.22 2003)" (some of the songs are the best version IMO - "Black" is ... huh... chills. Audience sings the whole outro - PERFECTLY - while McCready's Strat weeps)
and then of course Pearl Jam "Live at the Garden - [2003]" DVD.
Creed. Their "200?" Reunion DVD is TOP NOTCH. Not acoustic at all, but brilliantly recorded, audio and video.
huh... many more...