It partially depends on what you are learning for, but Simplified characters are used in most of mainland China (the PRC) while Traditional characters are used in Taiwan and Hong Kong, areas that are more open to westerners. Simplified isn't just an arbitrary title, they do actually make learning the written language a bit easier (although not incredibly so). It was designed to increase literacy. So I would recommend learning Simplified as it's a bit easier to learn a lot more people use it regularly. However if you're planning to go to Taipei or Hong Kong, it'd be good to learn it first.

>>109
Yes, and of course languages other than Chinese, that are written with Chinese characters, generally use traditional shapes. the examples that come to mind are Japanese and (a little bit) Korean, Ainu, Sawndip etc

So if it's not for actually using Chinese (for example another language, or you are fascinated by the calligraphy, or anything else...) then I'd recommend learn traditional ones.

It's easier to go from Traditional to simplified than the other way around.

aesthetically I like the traditional characters, practically I would use the simplified characters more (I live in Beijing)

I used Remembering the Simplified Hanzi by Heisig (actually I started with Japanese ussing Heisig's Kanji book) and he goes on to explain that you will be learning to read and recognize both characters no matter what, but it might be easier if you learn the one you intend to mostly write first