Time Machine backup solutions (need opinions)

[Apocrathia]

Okay, so right now my setup for my home network is a Linksys/Cisco WRT610N, and a Mac mini running leopard (not server), sharing an attached Drobo via AFP. As of right now, the client machines back up to the Drobo.
I'm trying to decide if I should replace the WRT610N with a Time Capsule and point backups to it, while suffering a minor loss in network flexibility. I know the Airport Extremes aren't awful units or anything, I've just grown up using Cisco/Linksys equipment.
My other option is to setup Leopard server on the Mac mini and keep my time machines set to the Drobo. Which I sort of like this idea since the Drobo is a bit more failproof than a Time Capsule.
My need for an opinion is that, while (Snow) Leopard server seems like it would be the better plan, I live in an apartment with no option of a public IP, therefore rendering a lot of the nicer features useless. I REALLY want a VPN as well, which my ISP is screwing me out of. And no, I have no other means of acquiring a different ISP, I don't even have a phone line and the ISP also controls the cable tv lines here. So do you think (Snow) Leopard server would be a good idea within a closed network?
I sort of like having the non external IP for funneling BT traffic through the network under other's addresses. If I can convince my ISP to give me a public IP for some dumbass monthly fee, I might set up a Time Capsule or an Airport Extreme regardless to run the public IP through, and a proxy on the WRT610N. I don't know yet how I'm going to set my network here up. I'm in a college apartment, so I won't be here forever at least.

 

[belvdr]

Given the multiple threads/complaints about slow TC speed, I would stick with Drobo.

I'm not sure why many residential folks want VPN back to their network, but one possible solution instead is to SSH to a box on your home network, and tunnel connections across that. Much cheaper than buying OS X Server.

 

[Apocrathia]

The lack of a public IP prevents me from being able to ssh back into my box at home at the moment. I've considered setting up an autossh bind to a friends server so i can bounce back into my home system. I want to be able to get vnc/afp/http as well though, and that isn't possible short of clogging my network with ssh forwards. I'd like to be able to access my network via my iphone from wherever i am.
i haven't read anything about people complaining about tc slowdowns, however i haven't read much about the tc in general yet. I might as well save my money and stick with the wrt610n for now and just wait for dd-wrt to become better perfected on the device.
i only need the 10 client license of osx server, so i might as well wait until they start surfacing on ebay for cheap. there are a few options that server offers that i'm really interested in like update caching, spotlight server (i'd like to be able to spotlight my drobo over the network) and the advanced time machine options.