well, its usually cheaper to buy everything from one place than it is to buy from several.
if you buy from Dtek, you could get a TC-4, unpainted core, Danner 250GPH pump, and some 1/2" ID / 11/16" OD tygon tubing and that will be ok. youll need a fan and shroud for the core tho. good 120mm fans are cheap; you can find panaflos for well under $10 if you look.
im using some of these myself. you can build a shroud out of cardboard and tape. now if you dont want to build a shroud yourself, or you want something thatll look nice thru a case window, you might want the core combo. at this point you may as well get the TC-4 max-inline kit and a NB block.
now if youre buying from DDen, you can grab a Maze 3, modded core, NB block, and some 1/2" ID tygon 3603 tubing. the ehiem pumps are good, but costly. what you can do is buy a Danner mag-drive pump from Petsmart ([url=http://www.petsmart.com/fish/shopping/water%5Fpumps/products/product%5F770.shtml]here is the page[/utl]). you need to mod the Danner pump so it doesnt leak. you can do this buy sealing the housing with a $2 tube of Permatex water pump & thermostat housing RTV silicone (available at any auto-parts store). youll need a 1/2" MPT and a 1/2" FPT brass hose barbs as well, and you can get those at Lowes or Home Depot (youll need some teflon tape too if you dont already have some).
thats for an inline system (no res / airtrap). if you dont want to bleed the system manually for hours, you could build yourself an airtrap. just get a marine electrical junction box (from Home Depot or Lowes. costs about $7). youll also need some 1/4NPT 1/2" hose barbs; get those from Dtek or DDen. a tube of plumbers goop would also be useful (another $2-3). thats it; it shouldnt run you over $160 for top-notch stuff. GL