It's almost impossible to say what's the best looking case as different people have very different opinions as to what looks good.
I like some clean designs like the corsair Graphite (the grey and black one is very nice, few photo's do the paint finish justice) and I like some of the more "funky" designs (eg I still like the NZXT M59 http://www.nzxt.com/new/products/classic_series/m59) but I realy don't like the obelisk like cases such as the corsair Obsidian series
On the level 10, there is a new level10GT which is a more standard case with level10 styling http://www.thermaltakeusa.com/Produc...S=1341&ID=2039
In a strange way I do quite like the look of the thermaltake armor A60 http://www.thermaltakeusa.com/Produc...C=1325&ID=1968 but at £70 I don't much like the price http://www.ebuyer.com/product/234935
Same goes for the Cubitek Tattoo http://www.cubitek.com/products/chas.../features.html looks quite nice but is rather basic design and rather pricey at £70 http://www.ebuyer.com/product/266549
I do love the Cubitek Mini-Tank http://www.cubitek.com/products/chas.../features.html it's not small for mini-ITX and not cheap at £110 http://www.ebuyer.com/product/266552 however there's something about the look I just love.
I currently also really like the Coolermaster storm enforcer http://www.coolermaster.co.uk/produc...roduct_id=6715 at £75 it's not massively cheap http://www.ebuyer.com/product/262675 however the insides of a case hold a big importance to me as well as the outside looks and the insides here are a step up from any other case of the size and cost.
A big key here is coolermasters choice to make the frame wider, while many cases are getting narrower, the inside frame is the same as the HAF 912+ http://www.coolermaster.co.uk/produc...roduct_id=6643 which is a bit cheaper but not as nice on the outside.
The extra width allows for large cpu coolers, extra space behind the motherboard tray for better cable management and the use of big 200mm fans to keep the noise down and air flow up.
I do love the silverstone fortress FT01 and the new FT03 (I never liked the FT02, something about the proportions and shape put me off)
Even though it's got a couple of minor issues in function I do like the look of the Bitfenix Survivor and I love the use of a ruberised finish.
Finally I do like the LanCool K60 http://www.lancoolpc.com/en/product/...25&ss_index=62 for £65 it's not bad for value as you don't need to buy any additional things and a like the tooless features, that actually work, http://www.scan.co.uk/products/lian-...g-case-w-o-psu
Finally my personal best looking case EVER
The WiNDy Alcadia FX2000 in Black Night colour scheme
Polished (not brushed) Black anodized aluminium outsides and polished rich blood red anodized aluminium internals, very very high build quality and a price tag that will make you cry like a baby
Very hard to get hold of (esp this older model) outside of Japan, although WiNDY are now doing international shipping.
The ALCADIA FX2000R4 solid Black version was just 52,290 YEN or $637 or £394 (currently sold out )
http://en.www-online.jp/case/alexer_...r4/lineup.html
Now you may say, but that's just a black obelisk from the outside? to which I say no, it could be but the sculpted rounded edges to the bezel and the external chromed socket cap bolts break it up just enough to look great and not like a square block of black.