Avast Antivirus + Comodo Firewall.
The reason behind this suggestion is simply down to my personal preference, however I believe that Avast have a much better detection over malicious software than Comodo most of the time - of course it's impossible to say if one is definitely better than the other since Comodo may detect samples that Avast could miss - and Comodo Firewall will allow you to make use of the auto-sandbox mechanisms to help keep you secure; the Comodo HIPS is also preferred in my eyes over the Avast one.
However, Avast have a better detection (statically for example) in my mind, and I like the Avast web protection, therefore I have to suggest Avast for the Anti-Virus component over Comodo.
At the end of the day, try out both configurations and decide which one you feel most comfortable with using, you are the best person to decide which one should be used.