Reddit mentions of Mac OS X Lion: The Missing Manual (Missing Manuals)

I would recommend this book by David Pogue, a fun read.

0. Their plastic enclosure is obviously more prone to stress cracks and scuffing (than the unibody aluminum), but if you don't fall into the laziness of throwing it around and eating around it (see: the inside of your car) they can hold up very well. If the top case starts cracking, they're covered under a Quality Program and can be replaced at an Apple Retail Store.
   
   
1. Since you've got 2GB of RAM, you can upgrade to 10.6.8 (Snow Leopard) by ordering the $29 10.6 upgrade on Apple's site. I would probably stay there, but if you really want to make the jump to Lion (10.7, minimum RAM 2GB) you can then upgrade from the Mac App Store that Snow Leopard provides.
   
   
2. If it's an early '08, I think 4GB is your limit. Still worth the ~$50. I've used Crucial memory before, but I know there are some good brands/deals on Newegg/Amazon.
   
   
3. Not a programmer, more of a hardware guy :P
   
   
4. Most definitely. Quick and easy once you remove the battery and RAM door - slide the original out, buy a nice 7200rpm 2.5" drive and move the HD enclosure over, slide it back in.
   
   
5. If this is a frugal venture, you can check out third party options. Otherwise I'd say a new battery is worth it, but couldn't recommend much beyond Apple's own.
   
   
6. If you can work through a book the Missing Manual is well-written and details the overall OS. You'll learn some decent tricks/tips from r/Apple, and MacRumors' forums have been a long-time reliable source for questions/troubleshooting.
   
   Enjoy your new(ish) Mac!