Pretty much what brad s1 has said above. You're going to need to move things about to find out where the clunk is coming from - this can be very difficult to diagnose. I would advise against just throwing parts at it - if at all possible try to find the problem as it can be caused by pretty much anything. Get a big pry bar and jack the front end up so both wheels are off the ground. Make it safe with axle stands/chocks etc then lever each wheel up and down, forwards and backwards and so on and listen to every joint - you may need someone to do the levering whilst you listen underneath. I used a big screwdriver with the handle stuffed into my ear and the tip on each ball-joint, bush, bolt etc. whilst the wheel was being levered.
Hopefully you'll find something. In the most recent case on ours, it was simply the bolts for the upper and lower control arms weren't torqued up properly - as simple as that! Horrible clunk from the front, but when jacked up and being levered about, the movement was barely detectable. No parts needed, and 10 minutes to fix once the problem was identified.
Good luck!