I have just put together a prime kit (well almost.... getting a FA 31 to make me feel more complete as a pentax person
). I basically have two kits for two different creative zones. 1st is when I have to get a job done for someone else..... then it's the two zoom and a wide kit (17-50 2.8, 70-200 2,8 and a DA 15....and maybe a fast portrait lens).
But when I'm photographing for
me (inc on holidays) it's primes and a special bag that makes it all enjoyable. Definitely with primes I am more considered and take more wow shots but much less shots overall. I also like the option of going faster then 2.8 for the obvious reasons.
I love the way I can have the "it's all about me" camera bag and the "work" Camera bag.
Of course there are times when a mix of the two makes sense (I've been known to take a big zoom on holiday if it's use is anticipated)