here are a few pretty close to sterling:
my favorite by far: aquatic obsessions in manassas.. they just opened a new store (they moved and used to be called the cozy clownfish, now doing fresh as well as saltwater) and the staff is cool as hell and very knowledgeable.. when i went in today, they had salvini and manguanese along with the normal cichlid selection (also electric blue rams for $20 each, and some gorgeous discus if that's your thing)... clown plecs, juvenile silver aros, and two 20+ inch pacus. as far as oddballs they had axlotls, RCS, blue yabbis, albino senegal bichirs and a sick SW collection.. their coral selection is pretty ludicrous.. everything is really reasonably priced to boot. PM me if you need their store hours or whatever, i have one of their cards.. if it'll keep them open, i'll refer all the business i can. defnitely one of the best local LFS i've been to, they'll take care of you. (i swear, i haven't been there more than any other customer since they've opened hahah)
Oh yeah.. they have a bunch of used drilled 30 & 40 gallon tanks @ 60 cents per gallon.. and a bunch of used heaters, powerheads, etc upstairs for bottom dollar prices if you ask.. my roommates and I pretty much cleaned them out of 20G's, filters, and lighting, but there's still a ton of stuff up there.
Centreville aquarium is alright for fish (they do have a huge red devil for 20$ (IIRC.. could have been 30) right now, and a couple of galaxy plecos for relatively cheap) and plants too, just don't bother getting any dry goods there, they're hella overpriced... they do have a bunch of replacement filter parts for okay prices though.
Vienna aquarium and pets - lots of different tetras/cyprinids that you don't see much, a HUGE pond section with quality koi etc., a really nice saltwater selection, and you'll randomly see monster fish on the top rack of tanks from time to time, they usually have at least two or 3 (I've seen fully grown plecs, aro's, and various cichlids up there)... pretty nice place, slightly overpriced.
Petland in fairfax - FW stingrays (usually just the plain brown ones, not sure what they're called), random oddballs like mudskippers from time to time, pretty nice discus, and they always have a few different plecos, usually gold nugget plecs. pretty good SW selection with nice corals & bamboo sharks