Different complexes offer various amenities -- a pool here, a covered parking garage there. But if you plan on cohabitating with a roommate (yes, spouses count) there are certain features you just shouldn't live without. Locking doors are probably the most important feature in any multi-person dwelling, but they're often absent or nonfunctional in many apartments. Have an unthinking roommate burst in on you in the bathroom or bedroom a few times, and you'll be ready to live all by your lonesome long before your lease is up.
Speaking of bathrooms, it's also critical to find an apartment with at least two of them. Couples should opt for a double vanity if at all possible. It'll cost a bit more, but you'll wish you sprung for the extra $50 a month whenever you find suspicious hairs near your toothbrush or on your soap.