So im interested in plugging in my guitar to my computer (for this, i know, i will need ones of those converter cables).
I've seen in various places that people have software which lets them record and use various effects (such as reverb/delay) and also different amp models within the software to create a digital sound similar to that amplifier and stuff...

so does anyone know the best software that does this? im looking for something that will let me record, mix, add effects and feature modelling amps so i can get many sounds from my guitar.

guitar rig 3.1
The Line 6 TonePort UX1 has upgradeable amps so you can add more tones.
+1 Toneport with Pod Farm.

Other software is fraught with serious latency and computer configuration issues.