what kind of livestock are you planning on keeping in the 125? if you are going to go aggressive or large, then you will most likely want to use a protein skimmer, instead of relying simply on the ammonia and nitrate reduction abilities of the refugium.
If you are going to go community, there are several people who have been able to maintain tanks without a skimmer. Personally for your size tank, I would probably want to use a skimmer, but there are other people who will probably steer you the other way.
For reef, I wouldn't consider running skimmerless on a tank that size, purely because of the need for really high water quality, especially when you get to hand feedings of several types of food to several different inhabitants.
Let us know what kind of stuff you want to keep, and wether you plan to go with a skimmer or not, and we can help you a little more.
On a side note, if you dont plan on displaying your fuge, that is, you have it all in a stand, then the broomer rubbermaid tub sump and fuge setup will give you the most bang for your buck, allowing you to spend more on pumps, skimmer, and lights.