I LOVE BEAGLES!!!!!! I plan on getting one in the next few months. The only problem is that their bark can be very annoying. You have to train them young not to bark or just get use to it.
Two other great small dogs are a Rat Terrier or a Boston Terrier. Both these dogs rarely bark. My boyfriend has a Rat Terrier and my roomie has a Boston Terrier. Both dogs are energenic and friendly.
Rat Terrier
Boston Terrier
If you like the Terrier type dog, a Jack Russell is also a good dog.
ETA:
For those in the Central Florida area, my roommate's Boston Terrier is pregnant and her puppies are due at the end of the month. Her dog is purebread and the father is also a purebread Boston Terrier. (It's her boyfriend's Boston Terrier) She has the AKC paperwork. PM me if you want more info.