I've love my Antec P180b case. Though the fans that came with it have long since died, it's thus far been my personal favorite of the cases I've worked with. Some recent tinkering has revealed that it may not be the best for airflow though.
I would strongly recommend AGAINST the newer Antec p280, however. I received my first one from Newegg in an intact box about two weeks ago... and it had a very noticeable dent on the top. I RMAd it, and it was replaced by another one with a slightly less noticeable dent on the top. They seemed to skimp a bit on the materials in the p280 and from my experience, it shows.
As previously mentioned, the Antec P18x and P280 are very different. The 18x series are multi-layered, heavy, and seem to be solidly constructed. The P280 is lightweight thin material with some padding glued on or inserted. I would guess that the P18x series is mature, having had multiple iterations, and the P280 is rather lacking / immature with a whole new fabrication process and being new (thinner / less) materials.