Some things to think about, rhetorical of course :
How do you like to carry your bag? This is will narrow your search considerably.
Consider your life. What situations require a particular type of bag?
What color(s) are neutral for you? Or what colors would work well with most of your wardrobe?
Looking at bags can be overwhelming! There are way too many options. I was just at Zappos and they had something like 4000 bags... and that was just handbags. Yikes.
I like to make sure I have the following:
**a clutch for dressy occasions... don't need it often, but really need it once in a while
**tote big enough for a novel and water bottle
**cross body bag for quick shopping trips so I can be hands free
**straw-ish tote for summer
Another thing to consider: If you really love to wear color, you might prefer a neutral color bag that goes with everything. If you love to wear neutrals, you might like colored bags to add interest. I tend towards neutral clothing colors, so I use my colored bags much more than my neutral black one. Your mileage may vary.