Personally I wouldn't, but that's because I really dislike Lion and am currently loving 10.6.8: I've been running 10.7 through all of the dev previews, GM, release, and now dev 10.7.2. I've wanted to like it(I really do want to like it and use it), but it's got way too much iOS for my likings, and not just the inverse scrolling and stuff like that, but how menus are, how finder is set-up, just the overall "dumbing down" of it. I also HATE how spaces/expose was implemented, but I will admit that I think the way it is in 10.6.x is as close to perfect as one could expect, and don't want to change.
If I hadn't used SL before I probably would love Lion(because it's not so much that it's terrible), but SL is [imo] perfect(or as close to perfect as you can get, and with all my tweaks and hacks it's more or less perfect).
And SL is pretty light on resources, I have 5.72GB free with Chrome Canary, Postbox(giving it a shot and; $30, but I'm liking it a lot. It's set up a lot like Mail in Lion, and the Mail app is something they got very right in 10.7), iCal, iTunes, Word, Preview, as well as numerous background apps, hacks, and tweaks.