The best advice I can give is "
Get Samples!!". You can't decide what kind of chip you want from a picture - feel is important (
the most important factor to me).
If you are buying typical mass produced chips, the feel will be divided into three basic categories:
-Slugged Plastic - these are often described as "clay composite", they are injection molded plastic around a metal slug and weigh 11-14g each
-Plastic (without slugs) - these too are described as "clay composite", they have no slug and weigh 6-8g each
-Ceramic - these are also made of plastic, but described as ceramic - they can be slugged (11-15g) but are usually not (8-10g)
If you want to spend more time and money on your set, you can buy customized chips with your own design. If you go this route, you will have the same options listed above plus "compressed clay" which are mostly plastic (they may have some clay in them) and are hand made (that means expensive).
I belong to a Poker Chip forum where almost all the members own sets of casino used compressed clay chips made by the Paulson Company. They no longer sell to the public, so we all scramble around buying the chips from closed
casinos. These are, IMO, the best chips ever made.
There are so many factors involved in choosing a chipset (there's a whole forum with thousands of members after all) that it's hard to explain without knowing some parameters.
What game do you want to run?
-Cash or Tournament?
-Stakes?