I just went through this whole decision-making research process and read every single thread on here with "trainer" in the title. Oy. So let me save you some time. The two most popular ones at reasonable prices (read $200-300) seem to be the Kurt Kinetic Road Machine and the CycleOps 2.
"My predominant feeling is one of gratitude. I have loved and been loved;I have been given much and I have given something in return...Above all, I have been a sentient being, a thinking animal, on this beautiful planet, and that in itself has been an enormous privilege and an adventure." O. Sacks