TeX system for Macintosh, recommendations
I'm using Emacs (Aquamacs) for working with LaTeX on MacOS X and AUCteX is really great, but you seem to look for another alternative.
Did you already check the comprehensive list of LaTeX editors? LaTeX Editors/IDEs
The answers there also describe their features and advantages, so it's very interesting and a really really long list.
For MacOS X available are e. g. (in the order of upvotes)
- TeXMaker
- TexStudio
- TeXworks
- Kile
- and many other multi platform editors...
Exclusively for MacOS X, there's
- TeXShop (Free)
- TextMate (commercial)
- Latexian (commercial)
- Technicle (free)
- Archimedes (commercial)
- ...
I'm sorry, I can not comment on your TEXINPUTS question, as I do use only one such setting up to now.