I've been using a Fellowes gel Mouse Mat for about 5 years, and recently it's finally given up... Worn it out i guess, so my mouse can't read the surface properly, so ordered a new plain black gel mouse mat Love the gel parts, they're so comfy
thats personal choice. there isnt really a best for everything for a mouse mat as there will always be a small number that dislike specific mouse mate type.
I've used steelseries fabric mousemats, which are quite nice to rest your palm on, glides well and fits small spaces easily because the fabric can overhang, or go underneath a keyboard without fuss.
My first proper mousemat was a Razer Exactmat, works very nicely with most optical mice but has a tendancy to be "grindy" on the smooth (speed) side, quite expensive too, but wears well and i still use it 3-4 years after getting it (albeit at work x3), works well with most razer mice and similar.
Currently at home i use a Roccat Steel surface, it's pretty much identical to the exact mat, but looks nicer and was alot cheaper, alot of the roccat products are incredibley similar to the razer counterparts, and i use a roccat wrist rest in tandem.
Whereas I'm obviously old school, at home I use a mouse mat I got free from Maplins about 6 years ago.
At work, we all have big A2 pads of paper under our keyboards with calendars and various notes scribbled across them, the bit of that that sticks out to the right side of my keyboard works fine as a mouse mat , and when it gets mucky, you just tear it off to find a nice shiney new bit of paper