OP:
Be advised that if you upgrade to El Capitan, you -may- be unimpressed by the performance of your MacBook afterwards.
I realize that the
"perception of performance" is an individual matter, but I would caution that you may find the experience of El Capitan "running" on old hardware to be more like "walking" ...
Having said that, you might consider 10.8.5 (Mountain Lion) as an alternative. It's more "modern" than Snow Leopard, but still runs acceptably well on older hardware.
If you really are intent on trying El Capitan, you might want to upgrade your MacBook with an SSD. The "speed boost" you'll get from using one will probably make El Cap run acceptably well on your MacBook. A 240gb SSD from Sandisk or Crucial will run you about $70. I don't know how much different the process of installing it is on the 2008 vis-a-vis the 2010 MacBook Pro I have, but it was a 15-minute job on mine (using the right tools, of course).
A suggestion:
- Buy a 240gb SSD
- Also buy a 2.5" drive enclosure like this:
http://www.amazon.com/Optimized-Inateck-External-Enclosure-Tool-free/dp/B00FCLG65U/ref=sr_1_2?s=pc&ie=UTF8&qid=1462376802&sr=1-2&keywords=2.5"+USB3+enclosure+UASP
- Put the SSD into the external enclosure and initialize it with Disk Utility.
- Install El Cap ON THE EXTERNAL drive first. Use the setup assistant to copy over your current apps, accounts, data, etc. to the new SSD.
Now, boot and run this way for a few days.
Booting will be slower due to the USB2 connection, but once up-and-running, you should have a good idea of what using El Cap will be like (it WILL be considerably faster once the SSD is installed internally).
Why do it this way?
Because if you find you DON'T like El Cap, you can keep using your MacBook "as is", untouched.
You want to be very careful about doing an upgrade that "you can't back away from" if things don't go as you wish...