If you're playing multiplayer then you can manually export your characters before the final fight in BG1 and import them, including all their gear, at the start of BG2 but having done this on one occasion it completely skews the difficulty at the start of the game and I'd advise against it.

Building up cash and magical items isn't difficult in BG2 and if you try to avoid overlapping weapon proficiencies on your characters then everyone'll get something decent fairly early in the game.

Ah, makes sense. Thanks, fellas. Shame to have all this gold, potions, and gear just go to waste, but I suppose that's the way it goes.

I have read that some of the gear you have on your character when you export out of BGI will actually appear in as treasure in some containers in BGII.

This is the only way to complete the quest involving the golden pantaloons (so if you have the golden pantaloons in BGI, definitely make sure you have them in your main character's inventory at the end of the game).

Other than the golden pantaloons, I don't know what other equipment, if any, carries over in the same way.

This is a list of items that will get imported. You can get at most three items. You always get the Pantaloons if you have them. Furthermore if you have any of Drizzt's stuff, he'll be mad at you when you meet him, but you won't get to keep the items.

Golden Pantaloons*
The Leather Armor +2 (Protector of the Second)¹
Chain Mail +2 (Mail of the Dead)¹
Plate Mail +1¹
Studded Leather +2 (Missile Attractor, Cursed)¹
Chain Mail +3¹
Helm of Balduran²
Horn of Kazgaroth²
Claw of Kazgaroth²
Koveras' Ring of Protection²

*This is in the picture container in the first room.
¹Ilyich the duergar will have one (and only one) of these items. If you don't have any of these items, or it's a new game, you get the Mail of the Dead.
²The chest in Jon's bedroom has one (and only one) of these items. If you don't have any of these items, or it's a new game, you get the Helm of Balduran.