My own personal experience with Dell is...well, "Dell" is a four-letter word.
That said, in terms of longevity the hard drive will be the weakest link in the chain, as it's the only thing (besides fans) which has any moving parts. 2850e (512K, L2, 1.8GHz) sounds like the best compromise for what will essentially be a Net appliance; there isn't a browser, media player, or email client on this planet that requires 2 or more cores, so even if you're really big on future-proofing a single core would suffice in this case. Win7 runs on 1GB and I personally have had it boot and run on 512MB; Dell runs their RAM with nonstandard voltage so they can extort double the price from you vs commodity RAM. In addition, any more than 3GB will require a 64-bit OS; not a showstopper necessarily, just something to be aware of. On that note, I agree with the 3GB.
Win7 has the same Remote Assistance setup that XP & Vista have;
http://adacosta.spaces.live.com/blog...DB!24153.entry has an illustrated howto for just that; I've used it with XP and had no problems with it. Many of the farmed-out support contracts use that same thing and I've seen them charge upwards of US$200 a year for the privilege.
Sorry if this seems to have a negative spin on it, I just hate seeing people spend more money than they have to.