It depends on what line of Meguiar's you are talking about. There is the consumer line which comprises of Gold Class, the three step crap, body scrub cleaner, Scratch-X, and other K-mart type products. Then there is the Pro line which is Mirror Glaze. This is basically #00, 1, 2, 3, 4, 5, 6, 7, 9, 10, 17, 18, 20, 26, 28, 34, 36 39, 40, 62, 66, and so forth. Then there is the Body Shop line of products, most popular on this forum is #83 Dual Action Cleaner Plus. Then there is the Detailer's line which is comprised of high volume bulk products. Meguiar's All Purpose Cleaner Plus and Engine Kote are two products out of this line used in the forum. Then there is the Marina section, but I won't get into that. Ugh, lets not forget the Medallion line.
So If I had a choice of Meguiar's products only. let me babble off my list.
1. Meguiar's Dual Action polisher and full line of pads and backing plate (hey it is from Meguiar's but made by Porter Cable

)
2. 30 or so Meguiar's Ultimate Wipes
3. 20 or so Meguiar's Applicator pads
4. 30 or so Meguiar's Cotton towels
5. Gallon of Meguiar's Gold Class wash
6. Meguiar's C-2000 clay (hey its not bad clay, just a little harder to work with)
7. Meguiar's #1, 2, 7, 9, 83, hmmmm, and some of their Diamond cut cleaner (forgot the # for it) for polsihing out the paint with the DA polisher.
8. Meguiar's #20 for a polymer sealant
9. Meguiar's #26 in liquid for DA application and some paste for hand application
10. Meguiar's #34 Final Inspection for maintaining
11. Meguiar's APC+ for wheels and tires, interior cleaner, and vinyl cleaner, plus engine cleaning
12. Meguiar's #40 to dress interior, tires, and trim
13. Meguiar's Odor Remover
14. Meguiar's #28 Metal Restorer
15. Meguiar's #39 Vinyl Cleaner for heavy duty vinyl cleaning (wheel wells)
16. Meguiar's #10, 17, and 18 for clear plastic
17. Meguiar's Wash mitts and brush kit
18. Meguiar's tote to carry all this stuff around
Am I missing any aspect of tools/chemicals needed to detail a car?
I'm sorry for this post being so long, seeing if I can remember the Meguiar's line off the top of my head.