I generally agree with both other comments if you are just 'trying' out a major or have no real commitment, but just a strong interest to the fields you mention.
If you are committed and really plan to make a future in the graphics and animation fields (not for gaming, but for real work), then a G4 powered PowerPC with OS X is a good solution.
If you want to go the PC route and are committed to this industry, I don't think you ought to skimp on a video card unless you have a very limited budget. I think many college students tend to have more financial expenses or surprises than they expect, so even if you budget a certain amount for school, bump up your financial expenditure estimates by 15-20% and then really control your spending according to original plans.
IF I were to compromise on price, I would get a slower CPU (save $50-$100 there) and get a better video card (spend the extra $50-$100 here), not the otherway around. By getting a professional video card, even on the low end, it can easily handle accelerations from professional graphic and animation programs that other consumer cards don't optimize for. Of course this assumes that you have a professional graphics, CAD, or animation program or will be using such a monster for school. Most regular consumer cards are able to work fine with most professional programs, but there are limitations in capabilities and speed.
3DLabs makes mid range professional video cards that are in the price range of the Nvidia GeForce Titanium chipset models. ATI makes the Fire GL line and Matrox makes 'non-professional', but very functional cards also.
Most professional cards are not designed for gaming compatibility, but professional applications like you specified, so don't expect to play many games with them or expect stellar game compatibility. So if a GeForce TI4200 costs you around $140 with shipping, you should be able to afford to decrease the CPU speed by the same cost and go spend around $200 for a better pro video card like a GVX1PRO.
I agree, get as much RAM as you can afford. For the motherboard, select something that has APIC capability if possible, although it only has a single CPU slot. Asynchronous Programmable Interrupt Controllers enable more IRQ's and allow asynch I/O, so your threads and processes switch better between apps and don't tie your CPU to one process. Some boards with certain VIA chipsets have such capability, but I haven't used a VIA chipset board in many years.
If you build your own stuff, reliability and consistent performance is more important that absolute speed. For memory I would go with the type of board and memory which is ECC capable AND registered if possible. If this prevents use of certain types of the fastest memory or DDR/QDR, this would be preferable to using such memory and boards without these features. Yes, ECC registered memory is more expensive, but the reliability is far better.
As for storage, it all depends upon what type of work you will do. If you will do alot of animation/video editing, then large drives are important, and they quickly get cost prohibitive with SCSI. Nevertheless, SCSI is unparalleled in reliability and expansion ability and other capabilities. You can easily add internal or external drives without worrying about channel limitations of IDE buses (since only ONE IDE device on any IDE channel functions to READ or WRITE at any time). Furthermore, in Windows NT4, 2000, and XP, MS has implemented a virtual memory caching algorithm which allows the simultaneous use of multiple drives for caching if the bus is independent of other busses (in IDE/ATAPI cases) or multitagging in SCSI's case. So, if you set up an independent RAID array for temporary video editing speed and have separate drives (on separate IDE channels if using IDE) for boot/system (one drive) and for caching (other drive(s)), you will easily have the most reliable and stable system around. Your budget with future foresight and professional goals should be the deciding factors.
Most of all, if you have a significant interest in some particular system configuration or component, don't be afraid to invest $ in the configuration you need and would really like. Most people regret not doing what they planned and dreamed about, not the other way around.
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I forgot to mention that I recommend the following site for prices
http://www.provantage.com.