This is sort of a silly question. What equipment you will need depends greatly on what type of work you'll be doing. In general, if you're just trying to stock up a lab with the most basic components that you will most definately need at some point in time, make sure you have ALL of the following:
Resistors (LOTS of them)
Capacitors (ceramic, electrolytic, and film)
Megnetic wire (for building inductors)
Diodes (1N4148, 1N400x, zeners, schottky's)
LED's
Transistors (2N3904/2N3906, 2N2222, TIP31/32...)
Voltage Regulators (3.3V, 5V, 12V, and in different packages for different power ratings)
Hook-up Wire (don't forget it)
Breadboards / Protoboards
Microcontrollers (PIC or Atmel)
Any tools you might need (soldering iron, oscilloscope, multimeter...)
Calendar of half naked women (absolutely neccessary)
$500 can get you a whole lot stuff at futurlec.com. If this sounds like too much for you, I'd suggest figuring out what you want to design and what it will require before placing an order