My best: wind proof packable jacket from Decathlon - £10 and has proved an absolute lifesaver on many an occasion. Plus a Belgian style cap I wear under my helmet in winter made by Madison.
Worst purchases: The pear of bib shorts I've just bought from Evans' own FWE range. Absolute bloody agony in the bum cheeks after 20 miles. I thought the pad looked slightly thin, but didn't realise how quickly it would start to hurt.
What's everyone else's best/worst kit purchases?