2¢
I think all chips should be eligible. Casino or otherwise. I love pretty chips, and don't care who made them (though admittedly, if J5 made it is probably better than a casino's).
I also feel that single chips and sets should be included. John Lennon is in the Rock and Roll Hall of Fame, and so are the Beatles. As well there are some chips that stand out as a single chip (RedBelly's Bounty races to mind) and some that work best as part of an entire collection (thinking Bel-Air here). I know this muddies the voting waters a bit, but truthfully, I think something as important as a Chip Hall of Fame shouldn't be an easy process. Perhaps breaking up voting into quarters would help. Q1 vote on Chip nominations, Q2 vote for sets, Q3 casino chips or sets, Q4 final voting for inductees from each category.
On a related note, I have started building a Custom Chip Database. It started on CT October 19th, with Novachipper's Whisky Club / PGI 8v set. I also included Courage's $5 add-on, and his DCS IV Commem. When CT failed us, I used all new chip posts from PCF to include in the database, starting with Tommy's Sahara 25¢ / Garden City relabel. I included a post to each thread indicating "added to my Custom Chip Database", so each owner would know they were included (or accidentally excluded if they did not get that message). I intend to post the database quarterly, to help make voting processes easier in the future. The "Best Chip Ever" thread on CT was awesome, but mind blowingly daunting because chips were scattered everywhere. Great chips were just missed, because their thread was not stumbled across during the nomination process. As long as I am active on PCF, that will never happen again.
I don't have the time to troll every 2+2, HPT CT and PCF thread to find new chips. So other than the 3 CT chips/sets mentioned above, if it didn't appear recently on PCF, it is not Database worthy. No offence to any not included, I just have a life. A sad one admittedly, but it is still mine.