Mac Pro :: Time To Upgrade Original Dual Core 2x2,66?

Usually pick up a new mac tower ~4yrs or so and now that im halfway through usually more or less max it to the hilt to last me. Lately havnt had the time focus on trends of who's putting out the most rock solid drives, ram, and what the best setups are...so would appreciate some feedback on my simple upgrade project for the home office...My usage is primarily heavy photography in pshop, lightroom, etc and moderate HD video editing in FCP.

First off think its time finally replace my wrt54g linksys router with one that supports NAS via usb, firewire, or ethernet... Eyeballing the 610n. Goal is to backup my data via time machine over the network now.

So for this effort i'd like to pick up 2 external 1.5tb or 1tb drives here in order to support the time machine backups, suggestions? Currently have a couple seagate 500gb externals in raid 1 via usb directly into my tower for time machine backup purposes and they are low on space. I would most likely raid 1 these as well for redundancy. What's the deal on raid 5 & 10, do the basic osx disc utilities support that yet?

Current spec on the quad core mac pro tower is the stock 250gb drive used only for the OS and apps, plus a couple 500gb seagate drives.Like to pull the 2 internal seagate drives and replace with 4 of the most reliable 1tb or 1.5tb internal drives on the market, seagate & wd have usually treated me right. Like to run raid 0 on each of the 2 pairs internally for speed so id essentially have about ~2 tb of daily workable space. Are the 2tb drives there yet in terms of reliability & value?

Lastly as for ram, risers a & b both are paired with 512 in each slot for 2gb total. Thinking 8gb would probably be sufficient for my purposes. Where are the best ram deals currently for the quality stuff.Budget isnt too much of an issue, prefer to pay few bux more quality instead of crap though im a frugal spender. Figure ~100-200ea for the internal drives, bit more for the externals, ~300 for couple 4gb ram modules,~200 for the router...