Borderlands is fun with a quirky sense of humour and a nice look in terms of art and graphics. It's less of a single player game than something like Fallout 3 and apprently gets a bit samey and grindy unless you play online in the co-op multiplayer mode.
At least according to the revews -- Eurogamer I find very reliable
http://www.eurogamer.net/articles/borderlands-review -- I have only played it for about 2 hours this morning while nursing a hangover. Games like this I only ever buy when discounted 50% as if (worst case) I only end up getting a few weekends out of them then £15 is not so unreasonable.