A good quality high speed drill will work well in most instances. Try and buy a good brand like Cleveland or Precision Twist, Chicago Latrobe etc. Don't run them too fast if you are drilling something hard, and use cutting oil or coolant to keep it from getting too hot.
Becareful with carbide, if you break one off in a hole, you might have real problem getting it out.
IMHO carbide twist drills work best when used in a machine tool (like a lathe or milling machine).
