Time for a bigger/better interface... Which one do you think?

I am currently running an M audio fastrack pro, I want 8 xlr's and midi.
 
IF I bought tascam US 2000 (no midi) could I still uses the M audio for midi I/O while using the tascam for audio?
http://www.musiciansfriend.com/pro-audio/tascam-us-2000-usb-audio-interface
 
Or I was looking a the presonus Firestudio project Which seems to fit the task and the budget but means going firewire....   What are the pros/cons of firewire over usb interfaces?
http://www.musiciansfriend.com/pro-audio/presonus-firestudio-project-recording-interface
 
The saffire pro 40 looks good too but is $100 more than the presonus. It is also Firewire and has (from what I think I understand) the ability to be expanded upon via ADAT's
http://www.musiciansfriend.com/pro-audio/focusrite-saffire-pro-40-firewire-interface
 
Any help of input here is greatly appreciated.  (I hate making lousy purchase decisions!)

Just can not give you a definitive ya or nay about audio devices I have not used is what is meant. As to firewire or USB, it may depend on which computer you use. MacIntosh may have a firewire port built in already, where most PC with Windows do not. They usually all have USB ports though, so a lot of people are using USB2 ports but not USB3 ports yet.
I suppose you can get a firewire card though for a IBM compatible type Windows computer though, but the USB ports are already there unless you use a lot of USB devices perhaps.
I use one USB2 port, because I have no USB harddrives or anything else except maybe a new mouse that may need one.

I never had a problem w/ my Presonus and they are a good company, tho it has been years since I've had to contact them or use my old FirePod.  It was solid.

@

chuck - check my website.  I have soundcard recommendations on my RECORDING HELP page.  make sure you check BOTH pages - it's a little confusing the way it's set up right now, but there are TWO spreadsheet pages.

I would think that the presonus 1818 should be a good unit.  the only problem is that I have not had any experience with it on the forums or personally.  all of the units I have listed on my website are there as a direct result of having experience helping others on the forum or using them directly.

if they are not on my list then either I have no experience with them, or the experience I have had with them has been bad.  the 1818 falls into thefirst category, I've not had any experience with it.

but it should be a good unit!