I ordered the RED 1157-R45-T bulb from
www.superbrightleds.com -- they have 45 LEDs on them and are perfect for the rectangular, single bulb, rear lights that have the light vertically installed. I had the "extra bright" bulbs in there, along with the reflectors behind them, but the LEDs make a real noticable improvement. It's a five minute installation, and the turn signals work just fine. Here are some shots:
This is the bulb:
This is the OLD bulb, brakes lit:
This is the NEW LED bulb, brakes lit:
And this is both of them, LED on the left, bulb on the right, brakes lit: