hm.. For me personally, warming up goes a bit beyond the cold-warm hands. Specially if because I'm working or travelling, I need to practice at "indecent" times such as 7am or 11pm... So, for me is doing "warm ups" is more a time to dive into the playing, get my brain and my ears started and feel in tune (can this be considered a pun?) with the piano as well as getting my body working gradually and try to polish technique.
I spend about 30 min if not a bit more. I have some Leschetizki type exercise, scales (I chose one and work scales in 3rds, 6ths, and 10 as well as arpeggios, long and short in that very same key) and recently I've started doing Brahms exercises, I might do about 3 of them, once I feel they come easy, I change. Also recently, I've started learning Bach inventions, as a child I didn't do ANY (SHAAAAME) and they are so wonderful music! When I have finish this, I feel ready to work on my Chopin etudes, some I perform, others are still housework, or work into the pieces.
If you tend to get bored easily, I wouldn't do long exercise types of warm ups, but you could improvise your own! I believe Clara Schumann was very good at this, someone told me Brahms' exercises are an inspiration on those "warm ups" of Clara. (I don't know if this is true!)
But as mentioned before, you have to found your way. I have change mine many times, probably in 3 years time, I have change it again
M