first off thats great you like your shifters! it doesnt matter what anyone else says or thinks its your bike right. as far as campy goes acctually the shifters alone are cheaper most of the time than shamano and when you factor in you can rebuild them when they break its worth it to pay more anyways. i have campy chorus on 1 bike but prefer shamano or SRAM. i had a 105 shifter quit working on me and that was it i have to get new shifters now. i sure whish they were campy now! i could just have them rebuilt.
on the other hand before i bought this last bike i had never rode anything lower than 105 and was skeptical when i bought a bike with Tiagra on it. i was surprised when they (Tiagra/105 RD) shifted better than my older 105. the only draw back to them really is that they are 9sp. not that big of a deal if you are not use to 10sp and if you are still not that bad but i would prefer 10sp.
only problem is you cant just put campy shifters on with you shamano group. well ive read of ways that work (check out sheldon browns web page) but its ideal not to and i believe you have to use 10sp shifters and have a 9sp cassette in rear. then you are still running 9sp. so to buy a whole campy group wont be as cheap as just replacing the shifters alone. honestly though if you like the sora thumb shifters you have got to try campy out they have perfected it.