While I'm sure I miss some things from time to time I haven't knowingly bought anything with HFCS in it in years. If you buy fresh, unprocessed ingredients you don't have to worry as much. I also buy a lot from Trader Joe's or local farmer's markets when they are in season and while I don't buy everything organic I do by almost everything all natural.
For example, I buy almond butter that has only one ingredient, almonds, as opposed to Skippy PB that has hydrogenated fat in it.
It costs a bit more from time to time but it is an investment I am willing to make. Once you find a good local store it doesn't have to cost an arm and a leg to eat healthy.
If you have to pick and choose which foods you buy organic there are some that provide more of an advantage then others. Check out
this site for some suggestions.