which brand/reg?

[MPR]

Apeks or Aqua Lung.

Top Notch Stuff. Easy to have serviced. Breathes very nicely. I currently dive a Legend LX and wouldn't trade it for anything.

 

[fl_coastie]

Atomic, I love my ST-1 and my M1. They are a little pricey but they are awesome. Atomics are are made by the guys who used to make Scubapro's regs. Atomic is the way to go if you have the funds.

 

[jlgrimes]

If we are talking about getting a top of the line reg then Look at Apeks, AL, or Atomic.
If you do not want the top of the line in one of these brands then get the Atomics.
Why, because there is very little difference between the top of the line and their bottom of the line. Especially in their first stages. The real difference only lies in features, not performance. If you want the top of the line for recreational diving only then it's really a toss up between these three regulators.

If you think you may be doing technical diving at some point, I would suggest the Apeks. Although I believe all of these regs would suffice. I just think that the Apeks is slightly more attuned to Tech.
For Ice/Cold water diving, I would still go with the Apeks, I like their seal a little better than others. It's just my preference.
So really go with Atomic if you are mainly doing recreational diving in cool/warm water. Apeks if anything more.