That's a very broad range. I started out 2 years ago collecting limited editions and commemoratives. I abandoned that idea very quickly after talking to people in the hobby and finding out how many new issues were appearing weekly. Just to help you out these are a few specializations that collectors concentrate on:

1. By denomination (10¢, 25¢, 50¢, $1, $5,...) even $100s too
2. By MOLD (Hat & Cane, Christy & Jones H/C, small-key, arodie, diecar,...
3. By individual casino (some try to collect one chip from each casino within a geographical area)
4. By city or area (Colorado, South Dakota, Tahoe, Reno, LV Downtown, LV Strip, Indian, Riverboat,...)
5. Type (illegals, junkets, No Cash Value, tournament, tokens, roulettes, samples, fantasy, brass PMSC, altered,...
6. Color?

Interesting putting this together because as you can see, there are many choices to putting a collection together. I think one mistake is for new collectors to try to collect EVERYTHING, myself included. I collect general downtown LV, Pioneer Club, Horseshoe Club, Hard Rock, NCV, arodie molds. But everytime I get a new chip that does not fall into this category, someone, you know who you are, will ask, "Why are you buying that?". I guess it comes down to one thing...
'cause I like the chip.

So I'm sure others will help assist with this list of categories and tell you how they've deviated from their main core of collecting. Happy collecting and good luck on those obsoletes.