I have two bundt pans, one is a Nordic Ware and one is some kind of cheaper bakers special.
I would suggest s Nordic Ware and would suggest buying from Williams Sonoma
12 cup is the standard pan
there is also an anniversary nordic ware pan that states 10-15 cups which is also nice.
I learned to never skimp on buying cake pans, I have tossed too many walmart kmart pans i bought just because of the price.
If you do choose Williams Sonoma, they have there own cake release spray that works so much better than even Wiltons. It's called Bak-Klene ZT nonstick baking spray...works like a charm and you need this or something like it working with a bundt pan.
Good luck.