There is an app for just about everything.
I use my iPad for my
Denon AVR Remote (awesome app),
TeamViewer to turn on my HTPC and control my PC away from home,
Hippo HTPC keyboard remote,
XBMC HTPC remote,
Apple TV remote. I also stream music from my iPad to my Apple TV/Denon.
My BenQ W6000 projector only has IR, so I can only use IR apps, which means I have to use my IR Android since the iPad does not have IR blaster like Android.
I guess I could use my Sony Android tablet with IR Blaster to control everything. But I like my iPad a lot more.
There are ways to get around IR, but I haven't felt the urge to venture.