The Enhanced Edition does feature both expansions.
As for what you wnt to get: It depends
The Enhanced Edition features a lot of minor tweaks (e.g.: a stack of arrows now consists of 80 arrows compared to 40 in the original game; there's a very handy 'quick loot' bar), some nice gimmicks (being able to zoom) as well as an UI overhaul and using the Baldur's Gate 2 engine.
The latter also means that the Enhanced Edition now features class kits, just like Baldur's Gate 2 does, plus a handfull of new ones (2 monk orders, 2 more cleric kits, dragon disciple sorcerer, etc). There are also new spells (as well as those that are in Baldur's Gate 2) and a bit new content.
Assuming you're on board with those changes that the Baldur's Gate 2 engine brings with it, there are only two downsides to the Enhanced Edition (ignoring the:
1. It costs a bit more. :D
2. You can no longer create new party members once you've started a new game in single player mode. This is, of course, the way it was in Baldur's Gate 2. But if you're the type that likes to switch party members mid-game or add some more at some point in the campaign, it can become a really annoying fature.
Of course, there are workarounds for this problem: Copy your savegame folder into the multiplayer saves and add a new member in multiplayer mode. Or play the game in multiplayer (with no other players) form the start.
Hope this helps! :)