Adat in/out would be the optimum route if you mainly use 2 inputs but sometimes need more.  Babyface or Audient iD22.
 
The lynx stuff is superb, but is $2000 for 8 x 8.  However, you'll be pro level for each of them.  The USB works fine.
 
I'm happy w/ my TCK 48, but that is a FW unit.  And they had lots of trouble getting the drivers right, which is probably why they haven't stuck usb on it.  Shame, since it sounds really nice (esp. the DA, 12 x 10 + ADAT + spdif, top notch dsp effects). 

Adat in/out would be the optimum route if you mainly use 2 inputs but sometimes need more.  Babyface or Audient iD22.
 
The lynx stuff is superb, but is $2000 for 8 x 8.  However, you'll be pro level for each of them.  The USB works fine.
 
I'm happy w/ my TCK 48, but that is a FW unit.  And they had lots of trouble getting the drivers right, which is probably why they haven't stuck usb on it.  Shame, since it sounds really nice (esp. the DA, 12 x 10 + ADAT + spdif, top notch dsp effects). 

Seems to be around $500ish or so and in a "comfortable" price range.

 
Yep - the 'knee' of the price vs quality curve. Best value in a upper mid-range unit with generous I/O and both F/W and USB2..

While researching my own interface needs, I ran across an amazing dude, mikeriversaudio, who does extensive technical papers on interfaces... I have both the Forte and the Presonus AudioBox 44VSL and his two white papers for these answered all my questions about each... you should check them out and then visit his site and review his analysis of anything you're considering... I'm a google/infomaniac and I've never seen better discussions/analysis than his... I'm talkin' 21 pages on the Forte... NO FLUFF... and the 44VSL is longer...
http://mikeriversaudio.files.wordpress.com/2013/04/focusrite_forte_review1.pdf
http://mikeriversaudio.files.wordpress.com/2012/03/presonus-audiobox_44vsl_review_mikerivers.pdf

There's also the Fireface UC which seems to fit your bill and goes for decent prices sometimes. I've seen them for like 750 euro over here, not sure how it is over there. But a far cry from 2000. Personally, I do hear the difference between my mobile Fast Track Pro and my desktop E-MU 1820M. I'll upgrade to an RME at some point.

some great replies and I see some good reading in the links above...thx Vastman.
 
it's interesting the [older]PCI versions of the RME Hammerfall are just so unbelievably inexpensive, selling used on Ebay, but you'd be locked into a PCI motherboard in a computer.  It's really too bad there isn't a PCI>USB or PCIe converter...   which I know there is but it is so crazy expensive ($2k+ I seem to remember when researching), that make it unpracticable.... might as well get a new interface.
The RME Babyface is looking more and more desirable.
 

Rme has a helpful user forum as well, FYI.

I love my ucx. The real time FX are awesome. For me it justifies the difference between the uc and ucx. Also the auto gain is nice.

You might also notice the octamic xtc just for consideration. Considering how things may grow over time for you is sometimes well worth the effort.

thx gswitz....I'll check the forums as well.  Problem is this kind of *research* is almost as fun as actual recording !