I really like this thread- particularly the posts from people naming bands I've never heard of. I am going to find some time to youtube some of these bands and I bet I'll find some good ones.
To my mind, one cannot judge contemporary bands by the same standards as bands who came along during the prime of the music industry. Release schedules and artist development were completely different 30 years ago. Even a band like Kiss put out their first 3 albums in an 18 month span and they wen;t nowhere until Alive- and there are tons of classic bands that didn't hit until their 3rd or 4th album. that just doesn't even exist today, for the most part.
In talking about the last great band, I don't want to go back to bands like the Pixies or the Replacements. I think there are great bands popping up all the time- but the industry to build a 30 year career has completely vanished. I think Wilco is a great bands. Flaming Lips might be one of the great bands of the last 10 years. Fleet Foxes could be a great band. If you saw Super Furry Animals on their Rings Across The World Tour, it would be hard to not think they were a groundbreaking band. The White Stripes (and derivatives) are certainly a band that has influenced a generation of young musicians. The Black Keys mean a lot to a lot of people. The Strokes had that Velvet Underground thing where they really influenced a ton of band sin the UK, but I don't quite think they have it in them to put out another great album.