Personally, I would have thought that a fully functional firewall was more important than anti-spyware software (if there was a recognised definition of exactly what is included under 'spyware'!) so I would sacrifice Spyware Doctor if I had no other choice. I don't actually have a dedicated, real time, anti-spyware program, but my AV (NOD32) includes antispyware definitions and I have SpywareBlaster installed. I also run BOClean which is supposed to stop just about everything!
If you are inclined to look for an alternative firewall, check the results at Matousec;
http://www.matousec.com/projects/fir...ge/results.php (Note that only ZA Pro is listed, I believe that the free version got a fairly poor rating in the earlier lists). I have no idea how valid the Matousec tests are but I am, coincidentally, using Comodo. It can be fiddly to set up and I read somewhere that, if you don't have the Defense+ function enabled (which is the one that seems to cause most of the alerts), Comodo is only a fairly average performer..