Linksys. I bought a Belkin router for a friend of mine and within a couple months it got too hot and quit working. I've always had linksys and no problems.
I have and use Linux routers and wireless cards. I just find them easier to use and better performing then their Belkin counterparts. Linux is also more expensive too but worth the extra money.
I never had any problems with either, but I tend to go with Linksys. If there are particular models you are interested in, I find that just looking at the Newegg reviews is a good barometer for the reliability of that particular piece of hardware.
Belkin is flaky i have set up a few of those for people looking to save a buck... they always die.
to answer your question linksys... because belkin sucks. however i find that Dlink is a good reliable brand... usually a tad cheaper and usually rock solid.
as far as linksys vs dlink.... ? close probably technically linksys but not enough to cream over