I've used blueprint in the past for designing websites and it helped a lot.
I'm now considering developing a new site, but this time it will be a 100% width site (think google groups page). Blueprint had a liquid "fork" some time ago, but after some tests I didn't find it quite useful for 100% width (it's ok for 90%-ish pages).
So I'm on the hunt for a new framework.
For now the best candidate seems to be elasticss.
Is it a good alternative? Are there any others I should consider?