I've had success with a Foscam IP camera. It broadcasts via ethernet or wifi, sends real time camera feed to a smartphone. (I've had to buy an inexpensive app for my android, but it works well).
The Foscam does motion sensing, and its web server can email you, or use an instant messaging client. Its sensitivity can be adjusted.
It can also be set to take photos, or record video if it sees activity. Some Foscam model I believe also has a relay output for triggering a local alarm, as well as an input (so if it can't see an intruder, it can be triggered into action by a signal coming from another device, such as a pressure switch under a carpet or something.)
All in all I think such cameras (self contained, single units) are perhaps the best simple option for keeping an eye on your house while you're away, because they do so many things for one device and one price tag.
Being single devices it's also feasable to have them wired into a redundant power supply, so a power cut (as long as it's not a power cut that lasts too long), won't interfere with it.
For home automation, I like the look of the Denkovi relay board. It too has inputs (for things like motion sensors, or break beam detectors), and the big relay boards control mains appliances inside the home. Denkovi's boards have built in web servers too, so again, smartphone control.
When you put two products like this together, you get pretty decent home surveillance and pretty decent home control for a pretty reasonable pricetag.
I think any company or product that offers home automation AND surveillance as part of one product line is bound to end up costing a lot of money, because you'd be buying a large integrated system, rather than a couple of gadgets.
Find the right couple of gadgets and you can do what you need for less. Buy a large system that encompasses all, and you end up paying for every perk at full price.
For example, a friend of mine bought an office surveillance system. The unit supports up to sixteen cameras, but only comes with four. Imagine now buying such an elaborate system but only using two cameras, and only having one intruder sensor? Too much money for too little practical use.