All glass aquariums is a good brand. Take a look and see what you can find. I have a 25 gallon aquarium that I just love. It seems to be the perfect size for an office depending of course on the size of the office and the fish you intend to keep in such a tank. What fish are you thinking about for this tank? Do you plan on going with a planted setup or something different? For a planted tank, I would recommend an eheim classic 2213 or 2215 canister filter. They are a bit pricey but hey, you only get what you pay for. I have the eheim classic series running on two of my tanks and they have been running flawlessly to date for years now. If you do not plan on a planted tank,then I would suggest a HOB filter from the aquaclear series. Possibly an aquaclear 30 on each side or you can do a penguin filter by Marineland such as the penguin 350 by itself or penguin 150s one on each side. I have a penguin 350 going on my 25 gallon tank and it is more then adequate for filteration. However, I do like the idea of duel filters. If one should shut down for any reason, then you still will have one filter going still for your fishie friends.
Just some thoughts. Hope this helps.
Marinemom