I second the list by egmdobbs...I can't function on low carbs; mine are usually at 50-55% or I get dizzy and sleepy. However, I put a lot of effort into making sure they are good carbs...fruit and whole grains. I use the whole grain pasta; it is sort of an acquired taste but they are getting better as time goes by. I make a meat and veggie tomato sauce that is thick enough to be almost like chili (brown low fat ground beef or ground turkey, then put it in a colander and rinse it; this washes away a lot of the fat, then the crushed tomatoes and veggies and spices in a slow cooker), so I can get away with fewer noodles that way. It also enables me to combine a lot of protein with the carbs; if you do that, they don't tend to hit your bloodstream in as much of a rush and jack around your sugar levels. I always try to pair the two if I can...I found whole grain organic pretzels (I am a pretzel addict) and I usually eat them with lowfat cheese for a snack...again, the carbs with a protein.
You're right, it's all about trial and error and what works for you. I believe everyone has their own macronutrient ratio and to try to force yourself into, say, 35% or so after having had 70%, well, that is a setup for failure. I tried to go to 40% twice since January and my body rebelled each time with plateauing and making me feel like crap. 65-70% is too high, I also know from experience, and if my fat percentage got above 25% or so, I stalled in my weight loss. Just keep really detailed data on what you eat and your weight, measurements, and how you feel daily and you should have your answer as to what works best for you. Hang in there...it's a process, but worth it to feel at your best everyday!
And now that you don't have to be perfect, you can be good.