MOTU 8pre by MH Studios
I cut my teeth in multi-track recording with the Motu 8pre. This is a fantastic unit to learn with as it has 8 microphone preamps (no need initially for outboard preamps), and can be used either as a firewire interface or as an optical converter to ADAT. The ADAT I/O can allow for a total of 16 channels of simultaneous input at 96 kHz. MIDI I/O is also provided, and the 8pre can be used to transfer MIDI information to and from your DAW.
Sound Quality - In my experience, the sound quality of the 8pre mic preamps are fairly neutral, unless pushed. The quality starts really degrading when the gain is near maximum, and it seems that you have to push the gain for lower output mics to obtain a usable signal level. I would say the preamps are fine for condensers and dynamics, but may be unusable for some lower output ribbons.
Ease of Use - Motu makes some of the more stable and up to date drivers on the market making the 8pre basically plug and play on almost any system. I ran mine on Windows XP originally, and later upgraded to Windows 7 with no issues at all. Drivers are available for Mac as well.
Features - For my first interface, it had all the features I needed to start multi-tracking. The CueMix software provided by Motu can also be really useful to make a monitor mix while tracking. Also came with Motu's AudioDesk DAW software, but as the software is Mac only, I never had a chance to use it.
Bang for Buck - This is extremely easy to use and has amazing features for the price. Spectacular for beginners and great for those needing some additional preamps via ADAT at a reasonable cost.