Decent priced Network attached storage for home use with mac and PC

I have a macbook with lion installed , a ipad 2 , iphone 4,PC with windows 7 installed and a desktop with win 2003 server for work . I have a WD 1 TB portable h/d and a iomega 750 gig desktop h/d . I plan to buy a xbox ,apple tv may be and tv with DLNA support .

I am looking to buy a NAS which would basically allow me to manage my media and files . I have following requirements -


- should be able to centrally store and access/play the files ,photos and videos on NAS from macbook ,iPad 2 ,iPhone and PC with out issues .would like to know if there is certain types of video files/music files that can be played from NAS through any of these device ?
- Would like to watch videos stored on the NAS through TV & projector too
-Would like the option to play the music stored on NAS through other music device i may have .
- should have itunes server support. I want all my songs on NAS and should be able to access it from macbok or iPad 2 or iPhone
- Remote access content through internet easily without extra charges ,not only media but PDF files and office docs ,text files .This one is mandatory as i need to access a lot of my work related docs stored on my macbook from office and since i travel a lot ....need to access from anywhere really ..my solution till now is to carry around a portable h/d which is why i am looking at NAS .
- bittorrent support
- ability to add extra h/w to increase capacity.Something where i can just plug in a external h/d with USB to add storage . I already have a WD 1 TB portable one .SO it would just another TB to NAS.
- easy remote sharing options with friends
- RAID options to mirror data.Optional .
- upload and download files easily through internet from ipad macbook iphone and windows m/c
- should be able to back up both windows n macbook



I had looked at WD world ,iomega ,net gear ,sinology ,buffalo station etc etc . I am not vey much into n/w and stuff .So need help with picking the right one ....

You may want to look at D-Link as well. I have the D-Link DNS-323 and it works reasonably well (though not totally without issues) at most of what you have listed.
It may be able to do it all, but I haven't tried all of it. My main usage is for storage and streaming video files to my ATV2.

The only real issue I have encountered is that about once a week I have to do a cold reboot on it for my MBP to be able to see the drive. Not absolutely sure why this is, because my iPad is always able to see it.

Moved to correct forum "Other Hardware and Peripherals".

My Book Live Best Buy and Micro Center will run these on sale once in awhile.

I looked at the WD live review in macworld ...
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With the My Book Live’s remote access tools, you can also view pictures stored on the drive via an iOS device with the free WD Photos app. While it’s a nice addition, you can only view JPEG files, and no other media type is supported. That’s particularly disappointing, considering that other NAS devices let you stream music via iTunes, as well as sharing videos across a network.
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does this mean from a pc or mac you can access all files remotely and from a iOS device you can access only JPEG ?

Other feature that i was looking forward was having USB support so that i could plug my 1 tb wd hdd to the has . but this one does not have it.but still looking at features it looks a good one .Can any one using it share their experience?