OrCAD
From reviews I have read, Altium (previously known as Nortel) was very good, but in the past several years, the new versions haven't been very good. It supposedly had something to do with them changing the engine or something and being very buggy. There is also allegedly the problem that the company adds lots and lots of features, but does so before fixing existing bugs. As a result, the software gets more feature-loaded and complex, but all the old bugs tend to remain (and new ones get introduced).
The review also said the quality of the Protel/Altium software dropped off a few versions before Protel 99 (I forget which version exactly), but then got very good for "Protel 99SE w/ Service Pack 2" (you can still get fully functional demos of it online if you search) and then afterwards the quality has dropped off ever since.
I use OrCad personally. I like it because it can also do simulations and I am very used to it. I am also used to the format. It is also stable.
There was a very extensive discussion on a forum somehwere...I will try and find it again. It also had very very good reviews for some software called PADs, price notwithstanding.