Which one is less intensive on the PC when it comes to editing ?

And is their a significant visible difference ?

Why do people film in 24p ?

Pro's and con's ?

I always shoot 1080p25 unless there's a chance I want to slow it down, in which case I use 1080p50.

Regarding the strain on the computer in editing, it's really easy to create and use proxy media in FCPX. I'm editing multicam with 16 simultaneous angles on my laptop! Quite mind boggling!

24p is what the americans use, here in Europe, the standard is 25p.
24p (or rather 23.97) is also the classical frame rate of cinematic film.

Newer systems should be able to edit 1080/50p no problem. On my i7-3770s I multi-cam edit 3 layers no problem in 1080/60p. I can even see results of color correcting in RT.

(Adobe Premiere Pro CS6)

Excellent, I have the same CPU with 16gb DD5 RAM and a nVidia Card.

Plan was to give it a try recording random stuff before my next paid event just to make sure the PC doesn't have difficulty when it comes to editing.

Is 50p or 60p better for slow motion? and why do people record in 50p ... at the end of the day, it is going in to your timeline and being outputted to DVD for example. So why not just record in 60p for the 10 more frames?