If my favorite foods are milchig (pizza, lasagna), is it Ok, or maybe even required that I eat these milchig foods for my Shabbos seuda?
See http://halachafortodaycom.blogspot.com/2013/02/archives-hilchos-seudas-melave-malka.html?m=1 about melava malka:
"If one does not enjoy, or is not interested in eating a fleishig meal, many Poskim rule that it is totally acceptable to eat a dairy meal, as this can be just as respectable as a meat meal. Indeed this is the prevalent Minhag of many scrupulous Jews."
Seemingly, you're more interested in having the pizza, so it would be fine to have such a melava malka.
Also, see here http://www.yeshiva.co/ask/?id=2294 where Rav Avraham Perl says, "On Shabbat one should honor the Shabbat with whatever gives him pleasure. If one prefers making only one meaty meal, it's best to have it in the morning."