I have a 1000 sq ft condo on the second floor of a building. I've had a great dane, flat coated retriever, bull terrier, greyhound, golden, and german shorthaired pointer in there at various times. Great danes and greyhounds are among the top big dogs that will do well in a condo/apartment. A lot of people were amazed that I had a great dane when they saw me outside, I kept getting "I didn't even know you had a dog in there, let alone a huge one". Greyhounds are awesome dogs too - very quiet and known as the 45 mph couch potato. They like to watch tv and relax when inside and a couple short times outside will keep them happy (they're sprinters, not endurance athletes). Obviously, goldens and flat coats are great dogs but cancer is very prevalent due to overbreeding. GSPs are ridiculously energetic dogs - probably too much for a condo and thankfully I only had him for a couple weeks while my friends were on vacation. Bull terriers are my favorite breed but you have to tolerate a bunch of stupid crap as they're clowns 24/7. I have a mini bull terrier that trances (walks very slowly) to food and has a pretty good bully talk. My bull terrier wants to keep going during walks while the greyhound is ready to stop about half way.
Definitely adopt if you can. The local shelter has great dogs but if you have a certain breed in mind and no dogs from the shelter meet what you're looking for, either petfinder or a breed rescue will provide access to the breed. Mixed dogs are generally healthier than the pure breeds due to expanding the gene pool. Repeated breeding from a limited population is the primary reason for a lot of genetic and hereditary conditions (cancer esp.).
While certain breeds are better than others in a smaller living area, it depends on the dog and how much you take them outside. Most dogs are going to not do well in a condo if they get very limited time outside to blow off steam. I'd also strongly consider the amount and pitch that a breed barks. Little dogs bark more often and at a higher pitch than bigger dogs generally. Nothing worse than a yorkshire terrier barking at 2am in an apartment.