On my old car i use to run 195 50 15 Bridgestone RE 910s I liked the tires because they were soft and gripped really good in the dry and had an asymetric tread pattern that was good in the rain also. On the down side the were only a T rated tire so they were only safe up to 118 mph. On my new car I have 16s but if I went back to the 15s I would still go with the 195s just because in the 50 side profile it is lower than the 205s. If you can afford it Michelin makes a great tire in the 205 50 15 size in the MXX3 model. Its a V rated tire so it safe i think up to 148 mph but they are expensive. I am currently running the MXX3s but in 205 45 16 and I love these tires. The compound is hard as hell and the take some heating up to get them sticky but once up to temp.

S rated 112mph
T rated 118 mph
H rated 130 mph
V rated 148 mph
Z rated 148+ mph
ZR rated 148+ mph (but cna handle the heat for a longer period of time than the Z rated
now they are comming out with W and Q ratings and Im not sure what they are about but from what I have seen first hand the W rated ones try to imitate the V rated tires but the suck ass in quality.