As has already been said 14 Gauge/ 15 Amps. 12 gauge/20 amps. 10 30 amps.
To start with the 10 gauge will cost nearly twice as much.
Next is useing it. Some one said it was harder to use. That is a gross understatement. It is a monster to install in a receptical, even if there is only one wire in it. If you have two or more wires in the same box, it can be next door to imposible. You will end up with bad connections because it is so stiff you can't get it in the box without bending it several times and the wires will work loose from the wire nut while trying to do so.
Plus most recepitcals are only rated at 15 amps, unless you go to the 2 and 3 dollar 20 amp recepticals and that is the largest you can get for normal appliances.
I always use 12/2 w/grn. for recepticals and 14/2 w/grn for lights, even if there is a ceiling fan because it doesn't draw much juice.
If you want to upgrade to the best you can get, use what I said and buy the 20 amp recpticals.
I do put in 20 amps in certain places. Over the kitchen cabs., bath, basement, and garages. Everywhere else gets the contractor grade which is only something like 39 cents each.
12/2 is plenty good for a house and will carry all the amps anything will use for the household.
Anything that uses more than that will be 220/240 volt.
As far as the code goes, you can always use a larger wire for a smaller circuit, but that doesn't make it the best choise. If you go with the 10 gauge, I hope you have some really strong arms, because I hate wireing a drier, dishwasher, etc. that are designed for it. I'll never attempt to pull a regular circuit again with 10 gauge and yes, I have did it because that is all I had on hand, but never again.