My philosophy: Spend it early, Spend it fast.
As I'm going to end at the omega point of a fully maxed TH11 in 313.4 days (
http://coc.jmjeong.com/) it doesn't really matter what I upgrade next, as long as I keep my Laboratory busy.
In reality, I have some preferred troops and to get those maxed, I need 14+14+14 days (Giants upgrading now, followed by Golems and Minions) and I still need 3.5+5 weeks for the Royals + 6.25 weeks for the Warden .. so, all in all I expect to reach the full (utilized) offensive power of TH11 in a couple of months (bounded by the royals)
Throughout my progression, I've always spend DE as soon as I had enough for an upgrade .. any upgrade and I don't save up for a higher AQ level if I have enough DE to upgrade the King .. spend it early, spend it fast.
/Affront