I kinda wanna go with a dark blue (because... well... I've wanted to for practically half my life now) but I'm hesitant about putting bleach in my hair (not to mention permanent stuff isn't handy when you face the prospect of finding a job sometime soon) and the only temp blue dye has to be applied with a little brush, like for highlights (Despite the fact that it advertises itself as a temp dye, and not a highlight dye)
Oh, and the temp blue isn't dark blue.