I agree; it's too tough to have a checklist, b/c some bikes have "extraneous" parts, usually to do with multispeed drivetrains or suspension or what-have-ya. Also, different braking systems have different requirements. Here's a quick, singlespeed coaster-brake cruiser checklist:
-frame
-fork
-headset
-stem
-handlebars
-grips/tape
-seatpost (some frames will also require a collar)
-saddle (some posts will also require seat-guts)
-BB
-cranks
-sprocket (aka chainring, chainwheel)
-chain
-cog
-pedals
-hubs (front/rear)
-spokes
-spoke nipples
-rims (front/rear)
(you can often buy entire wheelsets with both hubs, both rims, and all the spokes/nipples pre-assembled)
-rim strips
-inner tubes
-tires
Now, there are always other accessories (fenders, kickstands, chainguards, bells, horns, etc).
And, any brakes other than a coaster will require levers; often, you'll need to buy the calipers (sidepulls, centerpulls, cantis, v-rakes), a caliper/rotor set (discs), or sometimes just the levers with special hubs (drums, servos, rollers). It is important to match the levers to the style of brakes. Beyond the brake/lever compatibility, you'll need to make sure the fork is compatible with the frame, and that the headset used is compatible with both the frame and the fork. The seatpost (and clamp if applicable) will need to fit the frame. The BB will need to be compatible with both the frame and the crank; in some cases, there will be adaptors. The pedals will need to match the cranks (1/2" vs 9/16"), and there are compatibility issues at play with the chain and the cogs/sprockets.
If you're running multispeed gears, with the exception of 2 speed kickback rear hubs, you will need shifters and, most often, a bunch of other stuff (eg, derailers, cassettes or other clusters, multiple chainrings, various indicatorchains and such for internal gear hubs, etc.)
Even having written all of that, i feel certain that there are some things I am missing. So. I hope this helps; you'll find this forum and other similar ones to be helpful once you've got your frame and some clear ideas on what you want, exactly.
regards,
-Rob