Poll : Becoming a Skillful Hold'em Player. limit or NL HE?

[Maulik]

I'm not sure what game I should play for many years to come. Rest assured, poker will be a hobby for me until I get sick of this like any other hobby.

I enjoy hold'em more than the other variations of these games. What is making this decision tough, stems on the fact I do not really have a preference for limit or NL.
Let us consider what game will make myself a more skillful card player. The idea is become as skillful as possible in a game. I am essentially treating each variation of poker as a different game.

Most of my play is online, etc.

Insight shared is greatly appreciated. My experience includes lots of SNGs and short-handed limit & NL games.