The ensemble would be a great unit for you! It has good conversion and good preamps. It's very similar to the RME Fireface 800, the conversion is on par but I suspect the preamps will be better on the ensemble, although the fireface is more expandable. Since you are a Logic/Apple guy, I guess it would make sense to go with the Ensemble.
I guess the rest really depends on what you want to do. 4 channels of good utility preamps plus one really solid go-to preamp would be plenty for a guy in your situation I'd figure. In that scenario I'd tell you to buy the same thing I'd tell anyone to buy:
Daking Mic Pre One. tons of clean gain, great metering. Great all around preamp. It's the same preamp section from our Pre/RQ and from the Daking IV that Andrew loves so much. It's really a solid piece of kit. I'm suggesting this based on what I know of you and on the fact that you don't want to spend a ton of money. It's about $800.
If you absolutely want to have a total of 8 mic pres (maybe you do...) Then get the
Sytek MPX4 for not much more (about $1000 landed I suspect). It's a really decent preamp and a really amazing deal when you consider it's around $250 per channel to your door. Honestly I wished we got two of them. Matter of fact...we still might!
What are you intending on recording though? These days I usually recommend that people with home studios keep their rig tight and efficient. A "less is more" kind of approach. Instead of a bunch of half-ass preamps I'd suggest getting one solid channel set up and having a few solid utility pres and calling it a day. No matter where you go in any studio, typically once the bed tracks are in the can, it's all down to one or two channels for all of the overdubs.
That being said my third suggestion would be a good stereo preamp. At which point I say the
Great River is a good solid buy. It's gonna cost you at least as much as your Interface, but you'll probably never out grow it.
P.S. Is Andrew back from vacation yet? I can't keep doing his job forever...