How to decorate studio apartment?

Oh-kay I found my dream apartment and I have an idea of what I want to do to decorate it---but I need some help; if you had a studio apartment and you had to do the following-how would you go about doing that:
-putting up some sort of divider in the apartment to make the bedroom area separate from the rest of the apartment
-how to add some color and dimension to the room without painting walls
-making a kitty friendly area (he has a tower and a window perch and a couple of beds but what should I do with all of it)
-creating an "office space" for school work that is small or that can substitute for another need as well
-how to maximize the most of your space (it's just going to be me and a couple of cats but I tend to have a lot of friends that have nothing better to do but eat my food and watch my tv, so I'll need sitting space and a way to relax after a day at work)
I really already know what I want but for that same token I'd like to see what other people come up with before I move.

Years ago when I had a studio, I got a futon couch that looked
good during the day but was a comfortable bed at night. I
used a bookcase to make a divider between the futon and
the small table I used for eating or studying. Next to the futon
I had a steamer trunk that my comforter and bedding fit into
during the day, it also held a small TV and odds and ends on
top during the day. I had a desk and small sewing table on
the wall across. I kept my dresser in the closet (the place
had 2 just outside the bathroom, so there was room to hide
it in there. It was a cute place, I really felt comfortable there
but after I got married my landlady thought it was too small
for 2 people, so we found a one bedroom place which worked out even better. Ikea has a lot of cute inexpensive
furnishings, figure out what you need and try a few different
layouts, you will find out what works best for you and the kitties.

IKEA has some nice studio apartment benefits