Since you're in Australia can you provide places you will be shopping on line so we can give you a better idea. I know those of you down under get raked over the coals for software.
BlitzenZeus is correct that an i5 will be fine for gaming. I went with the i7 for more cores for video and audio encoding. I rip all of my CDs, DVDs and Blurays and frequently convert from DVD to MP4 for mobile devices. Nothing like seeing Handbrake max out 12 CPUs.
I've been using a SSD for about two years now and am on my third due to size issues. I do not recommend anything smaller than 120GB for a SSD. If you store all of your data on the SSD you may need to go larger. If the cost of the SSD will put you over budget, go ahead with a mechanical drive or a hybrid. Otherwise, you will notice a difference in the SSD with boot times and load times.
I don't think you'll have any issues running three monitors with decent frame rates off a card that costs around $300 US. Of course the more you can spend on your video card the better. -- "Progress isn't made by early risers. It's made by lazy men trying to find easier ways to do something." - Robert A. Heinlein