I've got the GoT 1st Ed, and was wondering: is it better to get the 2nd Edition straight, or is it somehow worthwhile to get the two expansions (Clash of Kings + Storm of Swords), on which I understand the 2nd Ed is based on?
Having played both, the second edition is definitely more streamlined than the first edition. The mechanics and "feel" of the game are pretty much the same (although the new "Wildling" and optional "Tides of Battle" cards do make wildling attacks and battles more interesting), a few balancing tweaks, but the biggest changes are mostly aesthetic.
To me, just being able to play without messing around with the overlays from Clash of Kings is a significant selling point (second edition only contains one King's Court overlay to balance three/four-player games), but if you already have the first edition base game, I don't know that any of these benefits are really worth the jump.
Storm of Swords, for the record, contains a completely different game mode/map which is not included in the second edition (and which I have never actually played); it is, however, playable with second edition pieces despite being a first edition expansion.