Okay. Well, it's the next day and my nerd rage has subsided a bit. I've decided to whip up a quick and dirty MS Paint diagram for you to give you an idea of what the network topology on something like this should look like.
What Vigilante has suggested is a bit of a hack; the problem is, as long as you're using a single IP for everything you're stuck using NAT and port forwarding. Aside from that, your home network is on the same address as the server, meaning that you're visible to the outside world and someone sufficiently savvy may be able to break into your network. Apart from all that, with his topology as illustrated above, you're going to be behind two layers of NAT. Double-NAT is bad and has the potential to break stuff.
What you really want is something like this:
The firewall is marked as optional, but it is strongly recommended. The reason that you could possibly get away without it is because the server box itself isn't likely to be overtaxed, so you could run a firewall directly on there. Also, depending on your routing solutions you might not need it -- a lot of routers these days have stateful firewalls built right in.
Router 1 will have NAT disabled, and will instead route via IP. This is also why you're probably going to need a Cisco router -- so far as I'm aware, there are no consumer-grade routers that can handle a /30 subnet (although to be fair, I've never really tried to use one that way). IP 1 of your subnet will go to your HTTP server, while IP 2 will handle everything else and connect to your home network. You can stick any consumer-grade router on that port and it should do fine, although if you're going to invest the cash to do this I'd recommend a Linksys WRT310N, as they're quite nice.
It should be noted that cofiguring a Cisco router aint like setting up your DLink jobbie. These things are very complex. You'll need to SSH in and actually know what you're doing. Seriously, people take courses just on this alone.
With this setup it actually becomes fairly trivial to add additional servers to the network, although I can't imagine why you would want to. With the sort of connections available on residential services you're not likely to overtax the box even if you run HTTP, POP/IMAP, SMTP and FTP all on the same one.
The other problem with this setup lies in the fact that most residential service providers in Canada will not lease you any kind of subnet. The exception I'm sure of is Teksavvy, but I seem to recall you being in Atlantic Canada and I don't know if they offer service out there.
We've told you all the reasons this is a bad idea. All that's left to say is good luck to you sir.