I've been at this around a month now. Managed to lay hands on an 8GH/s BFL Jalapeno for around $300 on eBay before BTC shot up and everyone tripled their prices. Less than a week ago I picked up two TAV RedHash units and am now cruising along at around 225GH/s or so total.
I've toyed with the idea of a Prospero X-3, but have yet to pull the trigger (although leaning heavily in that direction).
As far as pools are concerned, I'm in the process of a few 24 hour test runs across multiple pools (Ghash.io yesterday, BTC Guild as we speak, then Slush and some of the smaller ones to follow). Looking to see which averages out the best. I know there is a tremendous amount of luck involved, and fees play into the equation as well, but just conducting more of a rough, non-scientific baseline so I know to some degree that I am maximizing my mining time.
Managed to pull right around .14BTC from a 24 hour run at Ghash yesterday and I'm tracking a little behind that with BTC Guild today (although only halfway through the run).
Nice! I picked up a BFL Jally that does a steady 7.5gh/s, did local pickup on Ebay for $260. Despite the reputation they built from the late shipments, I've gotta say I like the BFL unit a lot. It looks clean, was a breeze to setup, and it's been super-reliable. Just got another blade so I am pushing a little over 60gh/s now. Please keep us updated on your pool research. Have you considered a shot at solo-mining? One of my rigs found a block with a pool, it got me considering mining solo on holidays or just now and then to play the odds... But I guess there's always SatoshiDICE if I'm feeling lucky, better than scratch-tickets I guess
Good luck!