what would be the best recommended flash to start out with for this camera?
That depends entirely on the distance of your subject from the camera/flash. You can get by with a quite modest flash output if you are just photographing one or very few people indoors. If you are using a long telephoto outdoors to shoot sports for instance, you may need all the power you can afford.
I'm considering the canon speedlite 430ex, would you consider that a good place to start?
That will cover just about any normal need for flash illumination and you should find it will serve you quite well.
Note: you asked for the BEST... that would be the 580EX 2