Help and advice on new build

This is my 2nd post here and the first was this same question but I think I asked it in the wrong place.. anyway can someone help with advice for building a system..

I am partially on a tight budget of around $700-800 but can keep investing as time goes

I dont need monitor, mouse, keyboard and speakers

My current uses:
- lots of file zipping and unzipping (large files),
- photo editing (will be getting into HD video editing) but may be a bit for the video..
- I simultaneously use photoshop CS4 and a canon program called digital photo professional which both are demanding on my current pc especially ran together (lots of program crashes)
- I shoot photos for hire so i keep everything (which currently is being stored on external HD's mostly).
- I ingest around 30-40 gigs of photo raw files weekly, zip them, back them onto external HD and then upload to seperate location (another external HD)
- lots of downloading
- a lot of multitasking (as much as my current pc can do without crashing)
- I do play a game called Realflight simulator which is hard on most computers as it graphic intensive (so seems to be but I am no pro and not sure the specs)
- Be used as ftp server as I like running a private ftp for friends and family

What I would like:
- Strong computer thats fast and dependable
- allows a fairly inexperienced person to build ( built a tyan dual CPU system about 8 years ago so some experience but long time ago)
- easy to overclock (if I get the nerve)
- dont need fancy case but plenty of bays and professional appearance
- looking at learning/using raid (this can wait if needed as i am making it without it now and not even sure how/if it will benefit me)
- Kids ages 14, 15 and 3 so gaming is a thought but nothing serious
- With photo editing I have to keep my monitors calibrated with exact colors. I do use dual monitors so not sure if that plays a roll with the video card selection.
- nice sound quality but doesnt have to be competative - low on my priority
- capable of future expansion as funds become available

I plan to start burning a lot of dvd's for data backup if I run out of space adding external hard drives.. I am not sure if there is a better method of storing large files but if so maybe someone will pipe in...

I should be able to invest a couple hundred here and there until the system gets solid...

I had looked into the core 2 quads (maybe a q6600 or Q9400) but then keep seeing the i7 but not sure what i need. I just wanting the best bang for the buck

Suggestions?

PS - as I mentioned I asked advice under anther thread but then realized that was a specific thread and thought I may have supposed to ask here.. Anyway I hope I didnt screw up with my first couple posts...

Well actually you can get an i7 for that $800 but you can only get minimal spec-ed components in that build like cheap mobo, 3GB RAM at most, maybe 250 or 320GB HDD, low quality case and powersupply, a low powered graphics card...
But spending around $1000 can get you a very solid i7 setup...