Agreed MBH, save money on pens, air filters and giveaways(calendars, stress balls, etc...) dont skimp on your DVR.
That being said, make an assessment of what your needs are.
how many cameras, how many frames per second, ability to increase frames per second on inputs(hold up buttons, alarm signals, etc...).
Many manufacturers provide a worksheet to input this information to determine the appropriate size of HD on your DVR. You may be able to save a few dollars there. Although 4 grand doesnt sound too unreasonable.
I'll be in the hospital bar.
Uh, you know there isn't a hospital bar, Mother.
Well, this is why people hate hospitals.