Storage for servers??

[WipeOut]

I know this is a little off topic but I thought I would give it a try 
here anyway becasue I think the people in this group are the right kind 
of people to answer my question..

I am going to be setting up a couple of servers in the near future and 
these servers will have ever increasing storage needs..

One server will be a web/file server and the other will be a mail server..

I don't want to keep moving the data to bigger drives, I want to have 
the servers use a shared storage facility that runs RAID and that 
capacity can be increased as needed.. Preferably using ATA or SATA 
drives to keep the cost down..

I have looked briefly at things like SAN's but these are far to 
expensive for our limited budget..

I have also thought of NAS but I am not sure the access over 
NFS/ethernet will be fast enough.. Even gigabit ethernet may become a 
bottleneck.. I guess I could put a gig ethernet link between each server 
and the storage server so each server has a dedicated gig ethernet 
connection..

Anyway I guess you get the idea about what I am trying to do..

Has anyone setup something similar that didn't cost massive amounts of 
money??

Anyone got any pointers to sites or products that would point me in the 
right direction?

Thanks