yes, look for anything 'extra' that has been added to your computer and network/router (cards, in-line things plugged into various connectors) and identify that everything is there.
if you are truly paranoid about this, then i suggest a full re-install after doing a complete wipe of the hard drive. yes, it's a pain in the butt, but the best assurance you can get. had you pulled your hard drive (without booting up) and had it forensically examined, you would have known whether or not it would have been accessed during your absence.
if this really was some type of espionage, then i sincerely doubt any mainstream software is going to catch anything that has been installed on your computer, unless it's really REALLY good software. for someone to go to this extent just to physically install spywear (especially when it can be done much more easily over the internet) then they're going to use something that isn't 'mainstream' (IE- out in the wild) and probably hasn't been identified.
if you're unfamiliar with the ins and outs of the phone/cable box on your house, then you may need to have a professional check things out. but really, if their goal was to install hardware to intercept communications at that point of access then they wouldn't even have to enter the house for that.
and if you're really going to go that far, then you're also going to have to sweep for bugs also. they actually have such devices you can purchase on the internet, but i don't know how good they are.
so there was nothing of place? no oddly placed bag or pillowcase laying somewhere? honestly, it really sounds to me more like a 'professional' burglary, but they got scared off. but i suppose it's better to be safe than sorry.