I would suggest either the Black Watch or the Black Stewart. Both are very nice, but a little more subtle. They do have a bit of a limited selection. They keep costs down by making kilts in quantity, and so concentrate on the more popular tartans.

Kilts can definately be worn without hose and flashes. Typically a nice black boot with higher socks scrunched down - my favorite casual look. Really you could wear just about anything with kilts. I personally think the hose & flashes make a better formal look.