Don't forget the original HS. Its one of my favorite games and a nice one can be found at a reasonable price. FH is also a great game but they are getting expensive.
In the last 6 months I have added Jack*Bot, ES, WW and Grand Lizard to my collection. I would have to say that JB has the most "Just one more Game" quality. But all are great games and not too difficult to find. Except for GL. I was lucky to find one and even more lucky to obtain a NOS clear coated PF.