I have a Carrera Subway 8 and I would like to change out the Suntour SR crank for something a little better, plus I think I gave it a bit of a knock and its not quiet that same any more.

Any suggestions?

shimano deore would be a good worthwile upgrade and will still keep in with the black look of the bike.

Thanks, is this a single chaine wheel?

and is there anything around having the correct number of teeth or anything else I should watch out for?

what about te truvativ isoflow? I have one and it shifts very well and is quite stiff (oooh err)
http://cgi.ebay.co.uk/Truvativ-Iso-Flow-Chainset-175mm_W0QQitemZ7175886681QQcategoryZ109118QQrdZ1QQcmdZViewItem

£31.50 + £5 p+p

or this for £26 all in truvativ x-flo

http://cgi.ebay.co.uk/TRUVATIV-X-FLOW-CHAINSET-170-24-34-42-MOUNTAIN-BIKE_W0QQitemZ7175486904QQcategoryZ42329QQrdZ1QQcmdZViewItem

deore hoolowtech chainset in black for £42 all in

http://cgi.ebay.co.uk/BRAND-NEW-BOXED-SHIMANO-DEORE-HOLLOWTECH-CHAINSET_W0QQitemZ7177057003QQcategoryZ56193QQrdZ1QQcmdZViewItem

I really need a Single ring, as the Subweay has the Nexus 8 hub and no derailer.

Something like this

http://www.chainreactioncycles.com/Models.aspx?ModelID=4011

but note sure about all the size options?