[QUOTE=Jess]I shall definitely give it a go, I think. The artifacts thing doesn't bother me so much - I always feel kind of sad when I find great weapons that just aren't as good as the stuff I already have. Can never bear to sell them, either

What does Tales of the Sword Coast add?[/QUOTE]
Me too, I keep all my unused magic items & weapons in chests in the Friendly Arm Inn, so I can open them up and say Check it out!
TotSC adds:
- overall enhancements to the game engine
- a higher XP cap, from 89k to 161k
- new spells and items to use
- new areas to adventure in
- a more challenging finale to the main game
Also remember to use the TotSC patch only (the expansion itself already installs the main game patch). And if you buy the "Baldur's Gate: The Original Saga" retail version of the game (which includes the expansion), I don't think you need any patches (it already comes patched).
The expansion adds an area to the main map, Ulgoth's Beard, located northeast of the city of Baldur's Gate. From there, quests will become available which lead to other new areas, including an island and tower, as spoiled in the previous post.
Your dudes can journey to Ulgoth's Beard at any time during the main game. Beware!-the expansion areas are designed for high-level characters (relatively speaking). I personally did the expansion during Chapter 5. All my dudes were well beyond 89k XP, and it didn't break any story momentum.
I think the expansion is cool, especially if you dig BG2. It has a certain feel to it... almost as if Bioware was designing BG2 areas at the same time they were designing the expansion areas to BG1. I don't remember anything in the expansion referencing the main Saga's storyline, but still, a few good adventures to be sure. May the Force be with you in that Tower...