If you mean border punches, my favorite is the Fiskars apron lace. It's similar to Threading Water and the two work together well on layouts. I think it's easier to use than Threading Water, plus the cut out dots aren't so miniscule. Easier cleanup!
As for any punches, the most versatile are circle punches (buy every size). I like the Marvy ones because they are BIG, but I also have the Fiskars ones and Paper Shaper ones. I pretty much have every circle punch made, LOL. I also really love the Retro flower punches and square punches.
Only buy the lever punches or handle-squeeze punches. The kind where you punch down a button in the middle are crappy, in my opinion.
I have the Threading Water Punch and love it. After using the heck out of that one I wanted to expand and ended up buying the Sentiment Scallop and Upper Crest Border Punches by Fiskars as well as the Binding Edge Border Punch by EK Sucess. I feel like those are all pretty versatile.
I think the Sentiment Scallop really compliments the Threading Water punch.
I love all my punches! I have more punches than I should! I like the Fiskars - Border Punch - Scallop Sentiment because you can add a tiny heart or a tiny circle punch above that one and get different effects. I like to combine my border punches and punch above them with other companies punches. Have fun playing with the different results!