I've been REALLY pleased w/ Kodak Portra 400 for color. Good saturations but still yields very natural skin tones. It works in several different lighting situations and can be underexposed 2 stops easily. I've shot some indoor stuff under fluorescent lighting and the result was very pleasing.
Kodak is releasing the new Portra 160 soon which is sure to be a FAVORITE for everyone. If it's anything like the 400, every film wedding photographer will be shooting it.
For b/w, I've really liked HP5. The choices are seriously limitless. Experiment and find the look you love.
Personally, (and I need to try many more film types) I find that Portra NC or possibly the new Portra 400 is the best (subjective opinion here) for more natural skin tones. If you can use Ektar 100 under certain lighting conditions it seems to work pretty well sometimes for portraits.
I really really love the look of TriX400 for black and white portraits, it just blows my mind how awesome those always seem to look.
I don't think any ISO 400 film would be my first choice for shooting people in the middle of Summer in the Bahamas ISO 160 would IMO would be preferable, I was always taught to use the slowest film that was practicable for the job.