West Village Sushi
I used to go to Miyabi all the time (3rd btw 6th Ave + Macdougal) but it's changed management and not sure how it's survived. It's a little lacking in ambience, but affordable.
Yama (on Carmine or Houston) is good but the sushi is served in abnormally-large portions.
Taka (on Grove & 7th Ave) is my favorite sushi place, and while it's not cheap I think they still have an early bird special.