If i get a 4GB xbox 360 slim will i need to get a 250GB hard drive later(Read below)?

well i`ve got a 4gb xbox and it was about �50 cheaper and I got a new 250 gb hardrive off of ebay for around �29 so do what you wish but i found that way cheaper if you get halo reach you can not search for game types or play co-op campaign with your friends with 4gb