You know, I never even thought about an in tank model skimmer. When I mentioned it to some people over at Big Al's they said that they frequently get a lot of returns on those. I always take their advice with a grain of salt however as some of it has proven to be good but a lot seems to be just very strong personal preference.
I will look and see if I can find an in-tank unit that would work for 90g. That would be preferable as I do not have a sump (yet), and, when I set up my tank, I don't believe I left enough clearance for a HOB model (I only have about 3" from the wall
live and learn I suppose)