It really depends on what you need it for. The Terratec is a great card, and I've one in the past. The main reason I went with the MOTU equipment was for portability. I wanted gear that I could use on multiple systems instead of buying gear for each individual system. The gear I chose fit the bill because they were external, firewire(828) or USB (Micro Express) based, and could be placed in a rack for transport.
The Micro Express is half-rack sized. It can be used on the desktop, and is also available in a version that uses the parallel port version. Before anyone screams because I said parallel, it is still a feasable interface for this use, and actually lacks a latency issue with reguards to USB (which I found out after the fact, though not nearly as bad as audio). I also have alot of midi capable gear, and sequence not only keyboards but also patch changes on vocal and guitar processors, and hope to eventually even sequence my stage lighting. I wanted the multiple outs so I can separate the MIDI channels somewhat as well. This way, I don't have all the gear chained in a single MIDI loop. But enough about me.
It really comes down to your own needs and whether internal or external gear would work better. If you don't need more than 16 MIDI ports and don't mind snaking MIDI cable from one item to the next, the Terratec will do great. There are also a couple pci-card MIDI interfaces that will give you at least another 2 ins/outs. I believe MidiMan makes one of those, along with other external interfaces. This holds pretty close in the audio side of things as well, though the choices are much more pci-to-breakout box based. It should also be noted that although there are USB audio interfaces, they are mostly USB 1.1. USB was not designed for steaming data, so even USB 2.0 will send data in large bursts rather than a steady stream as in firewire. USB audio has the potential to drop out during a recording, and is also inherently latency challenged.
I hope this helps you out. I would suggest a few thing to check out, but it has been a long day at work and I'm a little fried. Check out what your local music store has, or pick up a catalog/visit websites such as Musicians Friend or Sweetwater Sound, and see your options are. Most manufacturers have alot of info on their sites as well.
Jarrett