I realize this may be rather late in coming, and you may no longer even own the FX-500's by this time, but the top tips in my book for this pair of phones are as follows:
1. ~ $15.00 USD: HiFiMAN/Head-Direct "RE" series Bi-Flange Silicone tip, sold as a kit at head-direct.com with 2 pair of Bi-Flange tips and a set of stick-on filters. Personally I find these sets to sound the best of the bunch, and collect the least wax, and they fit my ears very comfortably.
2. ~ $5.00 USD: KOSS "KE29" "Earcushions" for IEM's, nice fitting, good with mids and treble while slightly de-emphasizing but not excessively toning-down the bass character. the thickness of the single-flange tips may be bothersome. I found them a bit "floppy".
3. ~ 8.00 USD: SONY Hybrid Silicone Multipack, there's a range of sizes, but basically you get ONE pair in the size you find that fits you. These fit nicely, kind of "suction themselves into your ear cavity" and slightly place empasis on the bass.
5. ~ ??? USD: SHURE Black Foam Sleeve (decored) "Olives" (medium) (for me)
6. ~ ??? USD: Phonak Audeo PFE Silicone Tips: These fit well, feel great (a nice silicone elastomer material) and give a nice character to the sound. (Medium) works for me, but I wish they had a size between (Med) and (Large)... That would be ideal.. and of course... they dont. boo hoo.
ENJOY!
