One thing I didn't manage to see while wandering around Portobello (because I drew the line at climbing into people's gardens....this time....) was the extension done by ODOS Architects to a house on St. Kevin's Road. Completed in 2005, the extension breathes new life into traditional shapes, in the words of the architects themselves, "re-establishing the worth of the period home and stating the value of the new".
Below is a more recent project, their 3 mews houses, completed in 2009 and receiving a nod in this year's AAI Awards. I think the rhythmic powder-coated metal slats are particularly cool, though I think ODOS use a number of materials really effectively in their work. Drool over their portfolio here.
(Images via ODOS Architects)