I needed to have Snow leopard to be able to run iLife 11 but I'm not entirely sure what I've got for my money with Snow Leopard
I can't say i've noticed any difference, apart from the fact it ended my trial period of CS5 10days early and wouldn't let me use my old version of itunes
As for iLife, I mainly got it for the upgrade of iMovie, which having played with it, I can see a lot of user friendly improvements to how one operates it, namely a better timeline and the ease of adjusting sound tracks but I'm a bit disappointed that they 'still' haven't integrated the FX from the 2006 HD version
Meaning, one still has to have both versions, if you want the full iMovie range of capabilities!
Why an earth haven't they included these
I haven't looked at iPhoto yet, as its 'still' upgrading the database