Depends on what your site is based on. If your selling, say computer equipment, then maybe computerequip.com/net/co.uk/info or whatever you would like.
I think the experienced domainers here (not me) would say the best way to make money is to keep your wallet in your pocket. Spend a lot of time reading this topic and others, here and on other forums. And then start slow.
And if you really can manage to do all that you will be better than most of us. The urge to get in the game NOW is hard to refuse.
Depends if you wanna make money from traffic/income on the domain or to resell it. Most names to resell in com/net/org are gone... so like someone said above... save ur money.
If you must, there are still some gems left in the ccTLDs IMHO.