Best strategy for video security, package or separate DVR?
I purchased all of my cameras and DVR a la carte and found it to be a bit cheaper and you get what you wany. Ebay is your friend for finding the parts and components necessary.

There are many options available for DVR systems now. In this day and age you will definitely want something that is HD capable. There are a lot of systems out there called hybrid DVRs that can record both analog and IP video. This would allow you to have some cameras that are lower resolution in areas you don't require quality and also the capability to use HD (720p, 1080p) cams in others. These could even be wireless cameras.

AliExpress, SecurityCamera2000 are also good sources for equipment.

I purchased some cheap (400TVL) dome cameras off ebay, and replaced the sensors with 2MP (720p) Sony IP cameras and saved a bundle. Since you are tech savvy, I think you would enjoy tinkering with different cameras and camera technologies. Searching for "Board Cameras" on ebay, ali, or securitycamera2000 will yield many results that will enable you to customize your system to you specific needs.

Just keep in mind, most of this stuff comes directly from china so it may be hit and miss on quality and take 3-30 days to arrived, but I have yet to be burned...

Good Luck!