Next comes RAM, the minimum amount of RAM now is now 1GB, optimal being 2GB+. Again, RAM depends on the amount or type of applications you are working on or how many you have open.
Newer systems use DDR types of RAM, to obtain the speed DDR RAM provides you need to install the memory in pairs. Do NOT combine memory speeds or capacities, while your computer may seem to work with combined memory types this could lead to issues and the computer will not run at the speed it is supposed to run.
If you use a faster RAM module along with a slower module, the faster module will clock down to match the speed of the slower module, thus neglecting the speed gains you would get from the faster module. Same happens with computers with multiple video cards, get cards that are matched in speed.
Also make sure to investigate if the motherboard uses DDR, DDR2 or higher RAM, and what speeds it accepts. Some motherboards can work with only 667Mhz RAM while others take RAM of speeds from 667Mhz to 1Ghz and higher.
Choosing a processor depends on what you need to do. The faster the processor the faster you can get things compiled, rendered or handled.
There are 32-bit processors usually the older Pentium 4 based processors that are still powerful, especially the last ones to come out. The newer dual core processors are now 64-bit processors, this proposes some future proofing as future 64-bit applications will take full advantage of these.
Various applications do run better on 64-bit processors, some can even detect them on a 32-bit Operating System. Dual core processors are faster indeed (don't let the lower clock speeds fool you), and professional applications benefit largely from those. While running at lower clock speeds, dual core processors can process more data per clock cycle. Not to mention that a dual core processor is better at multitasking.
You can get away fine with most stuff with a 2.0Ghz dual core processor. One thing you have to be clear of and which is a common misconception is that dual cores do NOT
double the clock speed of a processor. A 2.0Ghz 64-bit dual core processor for example is NOT
a 4.0Ghz 128-bit processor, in this case you simply have two 2.0Ghz 64-bit cores running at the same time and both
cores are sharing the workload.
Computer Blu-Ray, HD-DVD, DVD-RW or CD-RW units are NOT only for burning music or movies.
They can also backup large quantities of data either for archival purposes or presenting work at some other place. Pick one that is a known brand, also, don't cheap out on the discs either.
You will find no name branded discs really cheap, these are fine for handing over work or files to someone else or storing non-critical data. These, however, tend to have readability problems a few months later.
If the data you are backing up is critical or you may need it later always pick media from a known brand, keep it in their box and DON'T handle the disc unless you really need it. Keep them away from moist places or those that are prone to fungus.
Next a media card reader, if you are working in graphics you need one of these definitely, not only because they can read the storage cards from cameras but you can also the cards as storage devices for storing and carrying regular data as well.
A media card reader with a high capacity card reader can currently store up to 8GB+ per card on those new HDSC cards. If you want to add a floppy disk unit that is up to you, it's probable you won't need it in this time and day but when you need it, you need it.
There are some floppy disk/card reader combo units that offer both in the same unit.
Fans: These will ensure proper cooling of a system, a regular system will run fine on a single fan. More powerful systems have at least two or four, if fan noise is an issue pick ball-bearing silent fans.
However, fan noise is not an issue if you are running 500w speakers on your system.