Hi Digiboy,
Well, the E-mu's are one of the best samplers around for generating real instruments. While if you were planning on doing mostly drums and bass with it, I would recommend an Akai, the E-mu's are much better IMHO at generating real-sounding instruments.
As you can probably guess, the samples are very important here. You are not going to get great orchestral sounds by searching on the internet. There are some usable sounds on the E-mu CD's supplied but, IMHO, they don't compare with the commercial orchestral sound libraries available. The Kirk Hunter Virtuoso strings, Peter Siedlaczek Advanced Orchestra and Miroslav Vitous Orchestral libraries are great. However, they are quite expensive too and one of these libraries by themselves won't do it all for you.
To get started, there is an orchestral CD by Prosonus (I think it is distributed by Big Fish but I'm not sure) is not bad. It's not in the same league as those others but it can get you started anyway. In terms of world sounds, you can probably find some adequate ones on the internet.
What you will want to do is save some of your most-used banks to the hard drive as loading times will be substantially reduced compared to your CD Rom. While 4 GB is not very much, it should be fine for now as you can leave samples you don't use very often on the CD to load from there.
BTW, you'll want to load up your sampler with 128 MB of RAM eventually. Orchestral sounds (good ones anyway) take up lots of memory.
HTH and good luck,
Fernando