If you're watching off-air ATSC channels, you don't have to worry about the Clear-QAM mess.
If you're only watching live TV, then dual tuners aren't important.
If you're using Win7, the apps included with the card get thrown in the trash and they don't matter.
If you're using Win7, compatibility is reasonably guaranteed for any card that works in Vista.
If you're doing this all on one computer, sharing the tuner isn't important.
To summarize, a single tuner in a single PC using a single tuning method (ATSC) is pretty much as easy as it gets. If you choose a USB tuner, be sure to have a powered USB hub ready if a direct connect fails (it might need more power than the port can supply). For a PCI/PCIe tuner, just make sure you have an open slot and remember that tuners tend to generate a reasonable amount of heat.
My #1 tuner suggestion is always the HDhomerun due to the crazy amount of options you have with it. Since its a networked tuner, you can use it (and share it) on any computer on your network. It's also a dual (ATSC) tuner and it can do clear QAM. Although, it's ~$150 so its out of your price range and probably more than you need.