Many of us would recommend the Pioneer 206 or the older model, 205 if you want a blu ray burner.
Prices have been dropping steadily on blu ray burners. The Pioneer 205 was over $200 for quite a long time. Its replacement, the 206 is now $129 at Newegg.com.
If that is too expensive, the LG WH10LS30K is $79.99 with free shipping from Newegg. It is probably the best compromise on performance/price.