The ETW specs are not that high, DoW 2 will be more acesserble, but long term ETW has far more gameplay, and there will be some great mods for it. An ETW demo should be out soon, so you could use that for aditional info. Have you played a Total War game before?

My main advice is ETW will have more gameplay, and will be more fun, but it will be a little more complex than DoW 2.