at the end of my tether - ds will not eat anything I want him to!!!

[meemee]

After yet another tension fuelled tea time I am totally at the end of my tether. DS (3) has always been very picky with food and I've never really managed a day when I feel that he's eaten a healthy and balanced diet. All that he really wants are biscuits and cereals but he has phases when I feel that he eats okay. Fruit and veg have always been thrown back at me although he will drink apple and mango juice happily so I'm not too bothered there.
Recently he has started playschool and he's upped the stakes and food is now a major battle.
Literally all that he will eat: biscuits, cereals, apple and mango juice, chips, sausages from those horrid bob the builder pasta tins (but not the pasta), wholemeal bread (hurrah!), hot cross buns, ice cream and he begs for chocolate and sweets (which he does not get!!!).
He is now rejecting all the things I used to be able to get him to eat like sausages, chicken nuggets, fromage frais, raisins.
If I dare to offer anything remotely healthy like grilled chicken and pasta it will literally get thrown on the floor.
We've tried eating at the table as a family, carpet picnics, all going shopping together, him helping to cook but to no avail.
He is pale, grumpy, waking at 5am starving hungry and I generally think it's a pure battle of wills.
A friend suggested only giving him food that I want him to eat but he really just will not eat it and then is awake hungry all night.
What can I do?????!!!! I am desperate to encourage him to eat. Any suggestions/ similar experiences with extremely tenacious kids?

On a 'good' day, my ds seems to eat a lot(ish) at b'fast, no lunch and then shoves tonnes of food in at dinner. I suppose I should look at how much food he is consuming in one day rather than meal by meal. He even fed himself most of his supper (macaroni cheese and broccoli bake). Why can't all days be the same?

Chinchilla, my ds generally eats VERY well, but there are still some days when he seems to eat next to nothing, but if you think about it, adults have days when they could eat buckets-full, and days when they're not that bothered.

BTW my ds gets his own breakfast most days now. This morning he had a banana, a small box of raisins, a babybel cheese and a blueberry muffin. I think thats fairly balanced, and think he chooses well, because we have never stressed about food.