The Hoxton is OK, but a bit mid-range. Might hit the 'edginess' you want, but I think it's overpriced. (Mind you, lumping the IC and the Metropole in the same bracket is a bit )

The new IC at St James is nice but in quite a traditional part of town. There's also a Malmaison in London near trendy Smithfield, just avoid the standard rooms which I've found in need of some TLC. Both properties are in interesting buildings and just a little off the beaten track.

There's also a new Holiday Inn on Commercial Road depending just how far into the bottom right hand corner of the edgy area vs low cost matrix you want to go....