Rug delima

Basement is 99% done. It's time for me to go shopping. First thing first. I want to have Sophia's playroom part done first so that she can enjoy it early. To make the laminate floor warmer and also to define her playarea we deciede to buy an area rug. After shopping for the whole weekend I'm stucked.
Design? I wanted it with bright color, warm color, so that it can pop and warm up the area. But should I go with mordern design, a kid's design, or a geographic design?
Material? Wool or synthetic?
Thickness? Wzg insisted thiner one is better, but I like the plush feel.
Size? The bigger the better?
Budget? I don't want to spend a ton on a playroom area rug, we sure have a lot of other spaces need money.
Anyway it's a hard decision.