One of my upgrades on my 55 gl tank was a full length flex air bubble bar. My old air pump went out, noisy thing it was too and without enough umphhh to really do the job.
So I purchased a new air pump, Airmaster 3000 by marineland. Fairly priced & reseanable. I'm really likeing it, packs a good punch, I had to turn it down some even! Its very quiet and nice and came with a anti siphon valve as well.
Very nice, the folks at Marineland have done well!