Almost all the bushes, loose strut mounts...basically anything on the front end can be at fault. In my case, I was fortunate enough to get away with low tire pressure as the cause. Check the tires MAX PSI Rating and run your tire at about 3-4 PSI lower than the MAX PSI rating. For instance, my tires run a maximum pressure of 44PSI (NANKANG NS-1 if I remember rightly, 235/45R-17's all around), so I filled the tires to a pressure of 40 PSI. Eliminated the shudder... I'd check this first as it can possibly be your cheapest fix ever on your car!
Low tire pressure can also cause your tire bands to warp as a result of heat due to uneven wear. So if you do fill em up to 4PSI short of max rating, there still might exist a tiny bit of shudder due to the warped tire bands. But as DutchDaniel mentioned as well, the bushes can wear out over time and become old and brittle and need to be replaced.
No if only I can get that grinding noise figured out!
