I kind of agree with Antje. I don't like shuffling all my stuff from bag to bag, and potentially missing one or two things. I remember one day I forgot my lip balm in another bag and it soured my whole mood (my lips get horribly dry). I wouldn't want a collection of evening bags either, just because I don't have a lifestyle for it. One evening bag could probably last me an entire lifetime.
I have two everyday, bring to work/school bags right now and a few different weekend bags. The only distinction is size, and my weekend bags tend to be more colorful. I just don't like to carry big bags over the weekend.