Steady. :blush:
To keep all the bits in the right order, try getting a large dozen size egg carton or 2 and label each egg space for each stage on the ifixit. It's then a lot easier to follow the instructions back to putting it back together keeping all the screws and bits separate.
Have you thought about buying a 'Not Working / Spares Repair' macbook from ebay and trying the replacement yourself?
http://www.ifixit.com/Guide/MacBook+Core+2+Duo+Display+Replacement/536
It sounds a ball ache, but take your time, and get the right tools, and it's actually not too difficult...
My kids still my old PowerBook G4 from about 12 years ago, which doesn't do Flash, but they surf the web, and do homework on it etc. Still a decent enough machine to be honest. Not that the OP will want one of those, but that is the longevity you get as you've said.
Are Mac's expensive?
I bought a MacBookPro at the end of 2006, and 7 years later it is still a superb machine. It's an intelcore2duo 2.4ghz, max'd out with 6GB RAM, and it still handles Photoshop, InDesign, Web design, video very well. My wife uses it now, and I have a newer 2011 MacBookPro...