My laptop is 20 months old. It's already getting old. Luckily @driftwood's GOP1 made it easier to edit raw clips out of GH2VK. Now I really wanna bring the laptop everywhere... but it's been hassle to bring ext hdd. So I decided to install 2nd hdd. 1TB 9.5mm hdd :)
Since I have a unibody mbp, I ordered one from maxupgrades.com. Definitely overpriced but I don't wanna take a chance on a cheaper one from ebay this time.
I did this too - and you're right DO NOT take risks with the cheap ones - the connectors on the cheap ones are for shit, I went for a cheap one and it could not recognize the 2nd drive. I have 2 SSD's in RAID O on my 13" MBP - blazing fast and has not crashed or hung up once in 6 months. I highly recommend!
+1. SSD for OS & Apps. Definitely faster launching.
HDD for data. The internal HDD is faster than most or all "economic" external raid or raid-like solutions. The only bottleneck is the size of a single drive.