Buying one bitcoin today will for sure be a good investment in the far future. Once bitcoins infrastructure is finished then obviously we will grow in value.
I'm waiting for that point where alot of shops will be accepting bitcoin too and the value will rise then too.
1 btc can be a good investment to have but not the best one, if you are looking for higher profits then you should manage to have more then 1 btc as higher volume will give you higher profits.