I also have beige colored seat covers, light colors take in less heat but whites are difficult to maintain. For material I chose synthetic leather, which is durable, easy to clean, and economical.
I had put in Bridgestone's B700AQ, replacement cost was Rs. 3800 with balancing, not a single puncture since July 2006, while the car was used on under construction roads in Karachi on some occasions. A tip is not to change the overall diameter of the tire.
I do not know the benefits of alloy rims (apart from rust resistance) and they are too expensive for improving the looks in my opinion, so I am too running stock rims.