sr60's - they are the bassline and are a good indicator whether or not the grado sound is for you. They are at the bottom and cheapest so you dont have much to lose, John did a wonderful job capturing the essence of the grado sound in such a cheap package. First time i heard sr60's i fell in love with the sound, and knew that future upgrades along the grado line would merely offer refinement and technical ability, while still retaining that grado house sound - slam, detail, forwardness, prat, exciting!
a timeline of my grado journey:
60>80>325>225>old ms2>325i>RS-1>HP-2
PS-1's are left, i've heard them on various occasions and i like them, but my wallet doesnt, maybe one day ill be able to trade my hp-2's for them just to check them out, wishful thinking