Bpkid is right in that the brachy's and the Grammy's tend to grow slowly. Brachy's are the T's you hear about females making it to 20-30 years in age though.

The other two beginner species I was thinking of, are the Green Bottle Blue (GBB) Chromatopelma cyaneopubescens and the Pink Zebra Beauty (PZB) Eupalaestrus campestratus.

I don't acutally own a PZB, but they make very good starters, fairly simliar in temperment to a Chaco, but they stay around the 5 to 6 inch range. They are a pastel pink, where a chaco is a golden yellow and pastel pink and the PZB's do not posses a "mirror" patch on the abdomen, where the chaco does.

A GBB makes a great starter if you're not into handling. They change overall in color as they grow from spiderlings to adults, so it's a lot of fun to raise one from a sling and see it go through the color changes. It makes great webs and is very tough. Mine is also a great eater. Keep it dry. It's in the 5" to 6" range, I believe.

Most tarantula's fall in the 5" to 6" range. I'd recommend that you stay away from anything old world until you have experience with fast NW T's.