I tend to preorder stuff that I KNOW I am going to buy on release anyway, and lately it have been CEs of SC2 and WoW:Cata (never got around to the latter.. Preordered before i stopped the MMO life). If it's a product with some good quality in, yes I will preorder and get my stuff. The artbooks, the soundtracks, limited edition stuff, I like that kinda thing.
But to get to the Dragon Age 2 thingy, (funny, I was just looking at the preorder deal on steam). No in-game item in a singleplayer game will make me want it more or less. Personally I would rather play without the XP shield and scaling-with-level sword. I never redeemed my special gear in ME2 (the thing you got with an original purchase).
Bottom line: If I get cool collectibles and I am going to buy it on release anyway, then yes. In game items... Not so much.
But to get to the Dragon Age 2 thingy, (funny, I was just looking at the preorder deal on steam). No in-game item in a singleplayer game will make me want it more or less. Personally I would rather play without the XP shield and scaling-with-level sword. I never redeemed my special gear in ME2 (the thing you got with an original purchase).
Bottom line: If I get cool collectibles and I am going to buy it on release anyway, then yes. In game items... Not so much.