I'm kind of obsessed with the Microplane Box Grater, which I think is the best there is. It is a tad pricey, but it is 100% worth it. I've had it for 2+ years now, and it is still in great shape and still quite sharp.

I have a small microplane grater, which is lovely for finely ground things (from Parmesan to chocolate garnishes to nutmeg).

The best cheese grater I've found, though, is the Ikea one - it works well, it cleans easily, there's no crevices for gunk to get stuck in, the shredded cheese goes into a container (and not all over the work surface), it never spills over, and there's a lid to store leftover cheese easily. Plus, it's cheap. ;) This is the one I'm talking about: http://www.ikea.com/ca/en/catalog/products/50153180/

I have a microplane soft handle grater, zester, a kitchenaid four sided grater box and rarely use them. I always endup using the food processor with the shredder and grating blades. Especially with the soft cheeses like Mozerella. Arthritis is getting to me in my old age, another plus for the processor.

I just bought one this week! It's a Michael Graves grater from Target and it looks like this:

http://michael-graves.fashionstylist.com/michael-graves-grey-folding-cheese-grater-l.html

It has a hinge on the top, so it doesn't take up quite so much space. The feet are very sturdy and it's not small, allowing cheese to build up underneath it. I was thrilled it wasn't a box shape like my old one, which makes it much easier to clear.

These rotary style ones will grate even harder cheeses effortlessly:

http://www.amazon.co.uk/Kitchen-Craft-Stainless-Rotary-Grater/dp/B0001IWZJU/ref=sr_1_1?ie=UTF8&qid=1363639982&sr=8-1

I found mine, an antique 'Mouli' on Ebay.

I have this one and it is marvelous. very, very sturdy and stainless. no goo in the tightly rolled edge. everything I have in this line is great.
http://www.amazon.com/Kuchenprofi-1005122800-Jumbo-Rectangle-Grater/dp/B00008WUBE/ref=sr_1_5?s=home-garden&ie=UTF8&qid=1363642027&sr=1-5&keywords=kuchenprofi+grater

http://www.ikea.com/gb/en/catalog/products/60153189/

This from Ikea. I really, really, really love mine. In fact, I took it off my parents when I moved to uni and my mom bought another. She hated it so much that she had to go to Ikea to replace it :D It's good quality, easy to clean, and I love how it catches what you grate. I also like the fact that you can change the grating size panel.

This grater from Microplane is great It is much less bulky than a box grater, and is super sharp and sturdy.

http://www.amazon.com/Microplane-Professional-Extra-Coarse-Grater/dp/B0000CFFRO/ref=pd_sim_k_1

Also, how many people actually use all those different grating surfaces, like those on the grater pictured? I have one grater and one zester, and they don't take up nearly as much room as something like that. Much, much easier to clean, too.

I'm considering this one: http://www.amazon.com/gp/product/B003AKG6RS/ref=ox_sc_act_title_1?ie=UTF8&psc=1&smid=ATVPDKIKX0DER

also available here:
http://www.enricoproducts.com/catalog/cheese-grater-and-shredder-acacia-wood.html

I have a Zyliss white plastic rotary grater, plus a microplane grater. The Zyliss works really well for grating soft and hard cheese and cleans up well.

I agree with Ros for the Ikea grater/container even though it's not one piece. I use mine all the time (just tonight, even!). Love that it comes with a lid for the container too.

I agree with the mentions of the Ikea grater. Two different grating sizes, AND storage. I bought mine 7 years ago and still use it weekly.

My family has been using vintage nickel-plated graters for time out of mind and we like them enough that mum grabbed me a set from an antique store for my own kitchen. The stack neatly in a drawer [mine do anyhow] they come in graduated sizes and they're -really- sturdy. They look like these - http://www.etsy.com/listing/116163943/set-of-4-vintage-cheese-graters-by-super

absolutely the ikea one. the microplanes are also fantastic for very hard cheeses.

I have a big Kitchenaid box grater that I use for bigger grating jobs, like a few cups of cheese.

For everything else, I use a vintage stainless grater with various grating sizes, like the one pictured on the left:
http://urbancasita.files.wordpress.com/2009/09/img_65631.jpg?w=500&h=375

I have the microplane box grater, too, and I love it. It's a few years old, but it still works as if it's brand new.

If I ever manage to find a nicely priced vintage wonder shredder in good condition, I will love it forever. I always love using my parent's set. (similar to the ones linked above from etsy)

I have the ikea one, and wish it was bigger. Plus being plastic it's only a matter of time before my husband breaks it (although it's cheap enough to replace if he does). We had a plastic one with a handle and was perfect... except that my husband broke it. :(

I have a different one from Ikea, but Iove love love it:
http://www.ikea.com/us/en/catalog/products/50153180/

The container holds about 3 cups, there are two sizes of grater lids and a storage lid. The underside is rubber, so it doesn't slide around on the counter, and it's all dishwasher-safe.

I like the Ikea one! I got one a few years ago and haven't looked back.

Update: I ended up buying the Kuchenprofi recommended by lonibelle. I've got to say I disagree about the tightness of the roll on the bottom, it's definitely large enough to trap gunk. Husband's reaction to the new one, after months of researching and discussion on what makes an awesome grater, was "but...that's just a plain old cheese grater." I think we were both hoping for something a little more radical. My plan is to line the gutter with some sugru to prevent gooey build up. Will try to post a further update to let everyone know how that works!
Also, we found the missing plate to the Ikea grater, and husband has gone back to using that instead of cleaning the larger one.