For the SATA 3Gbps connection you've currently got, a number of SSDs can max it out. The best overall performance in SSDs are ones using the 2nd generation Sandforce controller, but over your connection, you're not going to notice any difference between those and the 2nd place Intel 510 series since the performance differences are not significant unless you're using SATA 6Gbps. And if you can get the Intel 510 series 128GB SSD for $250, I'd jump on it.
Based on some benchmarks I found for your SSD model, the Intel 510 should be roughly twice as fast for most applications, which is as fast as you're going to get without getting a SATA 6Gbps controller. In SATA 6Gbps mode, Brian's review shows that the Intel 510 series SSD gets between 50-100% faster transfer rates in real-world applications compared to the same drive in SATA 3Gbps mode, so the difference is significant.
As far as what controller to get, I haven't done the research on that, so I defer to Brian & his recommendations.