How to by the best one?

First Off what best describes your business lets say you're selling

model toys???

first thought that comes to mind is
modeltoys.com
Im sure that's taken so try
modeltoy.com

Or anythin relating to model toys or toy models. try staying away from just models as that can refer to human models.

The closer it is to what you're selling the more likely the name is to be remembered. be sure it no more than 2 short words too. One word is best.

Try looking for keywords through this http://inventory.overture.com/d/sea...ory/suggestion/

It's the most searched words through yahoo search engine for your type of site.