for a small tank, i like the concept of "found tanks" provided they're capable of supporting a bettas needs. for instance, i found this: http://www.walmart.com/ip/Anchor-Hoc...h-Lid/16486707
planted it first with an emerged dracenia, added driftwood to prop the lid, and put in some rocks, a heater and a terracotta pot:
then added smaller plants such as wisteria, primrose and hornwort, and now my delta boy Genghis lives in it:
the best things about it: the plants provide natural filtration and ammonia removal without the current caused by a mechanical filter, and it takes up about 1.5 square feet of counter space, perfect for a desk or office fish!