where do you live? do you have grates on the doors/windows? if you have those and a security sign, you are probably ok. i feel much safer in my city house with the grates than in my parents' old suburban house with a security system and much safer than i would in their retirement mountain house with a security system.
i'm assuming your city dwelling is smaller than a suburban spot. you will probably hear somebody breaking in, giving you time to grab your to ruin their day, as opposed to letting them sneak through a basement door, up your carpeted stairs and into your room. plus with with gates/grates, you present a clearly visible, not insurmountable but difficult hurdle. might as well move on to the not iron clad house if you have an option. also it will give you more warning/time to grab your weapon.
dont have carpet either. nothing but hardwood in my house. you can't sneak around for crap.
plus i would assume that break-ins when people are home are very very rare. A) its more difficult, B) I believe it comes with greater penalties. anybody who would do so is a bumbling crack head that could easily be dealt with
