Currently, I'm using my own software written with LabVIEW. It integrates 3\4 systems:
1) My insteon lighting controls.
2) My video surveillance system which is go1984 written by a company in Germany called Logiware. An awsome product with LOUSY technical support, yet I still paid $850 for a license because it does things with video motion detection no other product does. It also has the best region masking that I've seen yet for masking out plant motion from wind and such. Plus it's one of the few that can mix video sources from both video capture cards and ip cameras. I'm running a number of 1280x960 Toshiba IKWB-11A cameras and the detail is truly fantastic. I'm running pelco cameras in the areas around the property that don't have good light.
3) X10 motion sensors.
4) Dsc 832 alarm system.
Some examples of things the system does:
If it's night time and someone drives up to the end of hour cul-de-sac, the lights at the front of the yard come on for a short period.
If someone drives into the driveway, more lights come on closer to the house.
If the garage door is opened at night, the light inside turns on.
If the alarm is armed, various lights come on outside the house and various lights go on and off inside the house in a staggard fashion depending on which cameras and motion sensors are triggered.
If any of the breezway or back porch cameras are breached while the alarm is armed, LabVIEW throws a relay for outside speakers in those areas and using to text to speech, warns whoever is there that they are being recorded.
If it's during the day time and in the breezway, then it announces a friendly visitor message(UPS delivers to the breezway a lot).
If the phone line is disconnected, the outside speakers near the phone box announce that the phone line has been removed and that the alarm system is switching over to cellular backup. I don't actually have a cellular backup ;-)
If the power is cut, the alarm system tells LV and another message saying that AC power has been cut and the system is switching over to battery. The PC and surveillance system are on a UPS.
When arming the alarm system in away mode, various lights are turned off if on and things like our instant hot water dispenser which is on an appliance module is shut off.
If alarmed in stay mode, relays for speakers inside the house give us short text to speech messages when certain motion detectors or cameras are activated. The cameras in front of the house don't let us know as people occasionally drive up to the end of our cul-de-sac in the middle of the day. Our house is the only one on the cul-de-sac, so I get notified in the middle of the night if a car approaches because there's no good reason for a car to be driving up to our house in the middle of the night. This rarely happends. Of course the lights in front come on when they get within a 150 of the front yard.
We live in a low crime neighborhood near a city that has high crime and poverty. My house was broken into last year in the middle of the day. The alarm system scared them off. I now have a system that I feel will scare anyone off who isn't supposed to be there. Last year, all the of the lighted deer decorations were molested (made to look like they were procreating

. Ourse included. It happened again this year to every deer in the neighborhood, except ours. The culprit must of known we had surveillance system already because the night it happened to everyone else, nobody approached our house this time.
So back the original question. My own software for now, but I'm looking at homeseer too. I suspect HS will do most what anyone needs. I like having my own stuff for now because I know if I need something, I'll be able to do it. But it doesn't have all of the features that HS has...features I might use if I didn't have to spend time coding.