Media for Advice for SOHO firewall gear?

Advice for SOHO firewall gear?

I'm planning to expand my home/hobby network from a small gateway-server setup to a larger, more secure screened-network architecture, and I would like advice on firewall gear. My requirements:

- Minimal space, noise, and power consumption

- Stability and reliability (no lock-ups, no corruption, no hassle)

- Reasonable cost for home/hobby use ($500 is OK, but $5,000 is not)

- Firewalled routing from perimeter network (DMZ) to trusted network

- Support for both full routing and NAT routing

A three-homed routed with WAN, LAN, and DMZ ports is OK, so long as it supports filtered routing in both directions between LAN and DMZ. A traditional two-router setup is also OK, so long as the initial cost stays well under $1,000 and the power consumption is very low.

Here's what I've been considering so far, with approximate costs. Please add your own comments, and feel free to recommend other equipment that meets my requirements.

Watchguard Firebox X5 ($300 + $100/year): At first, this three-homed router looked ideal. Unfortunately, its configuration is not flexible enough for my needs. For example, you can choose to permit routing from the DMZ network to the LAN, but you can't just open a single port (e.g., for mail routing) -- the DMZ->LAN firewall is all-or-nothing. That means I'd need two routers, which is pushing my budget limits.

SonicWALL TZ 170 ($350 + $100/year): This is another three-homed router. I think it'll do everything I need, but I couldn't tell from the manuals (which I found confusing, even though I'm good at reading manuals). I've heard a lot of positive comments about SonicWALL, but a few users have complained of poor stability and support in the TZ line. I'd appreciate more data.

SonicWALL TZ 170 Wireless ($550 + $100/year): As above, plus wireless networking. Seems overpriced, unless the wireless features are a lot better than what you can get from a Linksys receiver. Is the combo worthwhile, or should I buy a separate receiver?

Cisco SOHO 91 ($250 + $100/year): If I understood the spec sheets correctly, this is a two-homed router, so I'd need two of them. I know very little about this box.

D-Link DFL-200 ($250): Another three-homed router. I have very little information about it so far, except some rumors that it's OEMed from a reputable high-end firewall maker. I haven't had time to read the manual yet.

Small-form-factor computer ($600): I've also considered building a firewall computer on a Shuttle platform. The higher cost and power consumption would mandate the three-homed approach, since two routers would be too expensive. The major problem here is getting three Ethernet adapters into a Shuttle box, since they only have one built-in port and one PCI slot.

Reconfigured server ($50 + much labor and risk): I'm planning to retire my existing server; with just a couple of extra parts, I could turn it into a dedicated firewall/router instead. Unfortunately, it also means that I can't switch to the new network setup seamlessly. I expect a lot more risk and hassle with this approach.