The principle benefit of dealextreme, IMHO, is that you can actually own these items.
Like, for real, my roommate has gotten techie things from this website. They do have pretty good deals on stuff like: wireless mice $9, plug adaptors for $6, and laptop cases for $5, all with free shipping. Also I see a number of stuff like toys that are $15 on thinkgeek but $3 here.
All in all, pretty useful!