I had a nice post typed out at work but never hit submit then shut my browser :dumb:
My insight would be to invest in the 430 or greater. I run a couple 580ex's and never looked back to smaller units. The main reason is the 430 will swivel and the extra power, you'll need it when bouncing light and using a diffuser. Trust me, it's worth it.
The key to photography is lighting. Get a good one. The 270 will be fine if cash it tight and all you're looking to do is average around the house stuff. However, the hobby is addictive and you'll find yourself at the top of the learning curve quickly. Mod bugs are just like cars. Upgrades await :masturboy:
Flash wise, whichever you get, look into one to two of these:
Stofen Omnibounce
http://www.stofen.com/images/OM_MZ3.gif
http://www.stofen.com/index.asp
Well worth the $20. Carries around easy and does wonders. You'll leave it on indoors wherever you are shooting so long as the ceilings are no more than 10ft.
The other is Gary Fong
I have both the Whale Tail Reporter and the Lightsphere II. Pricey gear but the flat out work and are by far the best I've used in terms of output.
Here's an image of Gary with them on his camera's:
http://www.garyfong.com/imagesdaily/garystudioreporter.jpg
http://garyfonginc.com/images/product/sizecomparison.jpg