My boys wear denim cargo shorts and khaki cargo shorts. Those are the only types I buy. I like how they look on them and they like wearing them. My youngest son has a pair of plaid shorts he likes too that a friend gave him. Honestly, I don't really pay much attention to fads since things change so quickly. I just don't have the time nor the money to keep up with them. A lot of our clothing is bought second hand at thrift stores since I just don't see the point of paying $10+ for something that MIGHT last a couple of months. My kids are hard on their clothes! If it's something for nice, such as holiday clothes or Church clothes, I am more apt to buy it new but not necessarily.
None of my kids really worry about "what's in style", etc. and my oldest is 9. If anything, they have a healthier self esteem because of that since they're not worrying what other people think. They're all clean and presentable with no stains or holes and that's all that really matters. My youngest son especially is great because 1/3 of his wardrobe is purple (all shirts and none of them are plain; one even has butterflies on it!) and he'll even wear a kilt. Even my daughter's don't worry. They like their bling, certainly but their clothing is a lot more demure than a lot of their friends. I don't buy anything with visible logos or licensed characters on them, nothing with double entendres, etc. Most little girls clothing is very inappropriate so be thankful you have a little boy to worry about! LOL
Just buy clothes you think your little guy will look cute in! Don't worry about what other people think; especially complete strangers. I'm not sure not seeing them on the models really matter; they're just pushing you to buy what THEY want you to buy, not necessarily what YOU need or even really like/want.
Like you said, clothes don't make the toddler. I firmly believe that the person makes the clothes. I have a friend who wears NOTHING but vintage clothes she finds at thrift stores and even complete strangers are always stopping her on the street and asking her what store is selling it. They're always completely flummoxed when told it's an article of clothing that's probably older than they are! (Mind, it's not that way for me.)