Selecting a new saddle

I have a knackered saddle that badly needs replacing. Criteria for
a new saddle include comfort (I'm a wimp) and that it shouldn't
rip holes in my trousers too quickly (hate that kind of waste).

I had a look in my normally-friendly&helpful LBS, and they have
a range of wierd and wonderful things, including some with holes
or slits in, which leads me to wonder how far some people take the
leg-over metaphor. However, they didn't seem particularly keen
for me to test-ride with any of them, leaving me unable to choose.

So, I'm looking for tips. How do I go about selecting a saddle
"blind", without risking a sore bum?

and - ahem - what are the strange shapes in aid of?


--
Finally, someone takes a stand against Humbug.
Three cheers for Austrian shop workers!