Some personal picks (some being not the most obvious, but i like them):

The Future: those eerie soundscape, the voice of the 'joker' then those sober beat coming in... sinister

Endorphinmachine: the guitar riff grabbing you directly by the throat

Calhoun square: the spoken intro, then those dry dum beat kicking in... i think this cut has been recorded live, at least the basic track

Eye know: the song 'emerging' from the chaotic soundscape / sounds

Sign of the Times: a classic, great drum programming, what more can i say?

Paisley Park / Raspberry Beret: on the first track Prince is counting off in a goofy voice, on the second, Prince does it in a 'proper' way, to me it sounds like he did this purposely, some nice little humoristic touch

Mia Bocca (by Jill Jones) - I keep promoting this track On the album an orchestral intro comes before this song, i always considered it part of the track, the contrast between the full (acoustic) orchestra, and the bare (electronic) beat kicking in after that, works brilliant

Escape - 'Snare drum pounds on the two and four, all the party people get on the floor'..then dry funky drum and bass kicking in, it just sounds very good

The Cross - this lonely guitar riff rising in volume from the 'silence', classic stuff, what more can i say?

Power Fantastic - Prince showing a subtelety and organic sound in his music i wished he would show more often

Although the song hasn't aged well, I love the intro to Get Off.
The scream followed by the desperate yelp used to have me and my friends crackin up. It's actually the song that converted 2 of them to Prince fans.

SenseOfDoubt said:

Yes! Whenever I am bored I grab my guitar and just play those intro chords over and over again. I could listen to those forever.

When Doves Cry and Adore are the best Prince intros--hands down.