If you get a compact, some roadies will consider you a lower form of life. If you get a triple, pretty much everyone except tourers and a few MTBers will consider you a lower form of life. And the tourers will consider you a lower form of life anyway because you haven't got enough spokes.
You can worry too much about it, just buy one. It may be worth considering what ring you're likely to spend the most time in: a 34, 39, or 50, because that may dictate what you want to have somewhere on your chainset. But you probably have no idea yet.
For me the key element would be the facts that (a) shifters are bloody expensive and (b) whilst you can use a double chainset with a triple shifter, you can't use a triple chainset with a double shifter. So if you're unsure then it may make economic sense to buy a triple.