I was about to jump in & say I loved it, then I thought about it and couldn't really remember that much about it. I think I started to read it, put it down for a month or so then picked it up later & did end up enjoying it, but as you say, I can't remember a great deal about it now which isn't a great endorsement.
Drowned World - I couldn't read, have read the first 40 pages a few times, never get further (despite loving some Ballard, The Drought is brilliant).
I do love Oryx & Crake though - The Flood - not so much.
Earth Abides I loved, particularly the last chapter when he's very old & confused but incredibly lucid about humanity.
Ender's Game, I thought was OK, just that, I enjoyed it, am entirely unconvinced by the massive plaudits it seems attract. It didn't seem to me to be a book that was revealing a great deal about humanity which the best Science fiction does. A similar, but much better and more affecting storyl is The Forever Wars by Joe Haldeman.
I Am Legend was a product of its time I think, his startling realisation at the end has a hint of B movie to it.
Love my post-apocs & science fiction (the harder the better), am happy to witter on with you all.
I like to mix it up with a bit of lit-fic every now & then, I accidentally read some chic-'lit' the other week. I had to mainline hard SF to get over it.