Not all routines have to be centered around a subject, you can in fact mix all of your favourites tricks with a few climaxes and make a routine.
But, keep that in mind, all tricks should have the same feel to them, the same atmosphere around them. For example, you can't do a light, amusing card trick and then jump to some serious mentalism stuff. For street magic use quick, light, visual and high impact tricks (Panic is a great example, or Distortion, and I also like Clutch by Oz Pearlman, though it's a bit longer). For party tricks, make a routine with one quick, high imapct starter, then a gradual build-up, when you slowly bring your audience to believe you can do anything with a deck of cards, and end it up in a more dramatic, slow effect with a very big climax (One of my personal favourites lately is Justin Miller's Blank Out from the Ellusionist's Guerilla Guide to Using Loops).
Have fun!