Skylanders Supercharger
This is similar to the Disney Infinity? Base with action figures that you can them put into the game yes? How do your 4 year old do playing that game?
My DS also asked for "science" stuff, but I don't really see anything that's appropriate for a 4 year old.
There is some decent science stuff for 4 year olds as long as you don't mind messes. Magic Schoolbus has science kits which are great for about 4 to 7, they have a bunch of different experiments in them, that they do need help with, but work decently for the age range. Also Thames & Kosmos has a Kid's First line which looks doable for the younger ages depending on how interested they are in science. Educents also has a slimy squishy polymer bucket for that age group, which I think is what I'm getting my 4 year old as his science gift this year.

But he has gotten really into Mickey Mouse Clubhouse and is asking for a plush Minnie and Donald to go with his Mickey. He just had a birthday and got new toys from his party guests so he's pretty happy with those at the moment. With a new LO on the way the last thing we need is more stuff in this house, and we won't have much room in our suitcases anyway. I'm hoping he'll be happy with the plushes, some stocking stuffers and maybe some new Mickey or Olaf pjs (and we're planning on taking him to Disney Springs to pick out more parts for his Mr. Potato Head, is that still there or has it become all Star Wars stuff?)My 4 year old daughter wants princess stuff, particularly Sleeping Beauty. She also got a hold of an American Girl catalogue a couple days ago and now has it in her head that she wants one of those too.
Oh and as a joint family present we got the kids a big set of Magformers. If you haven't used them, check them out! They are super fun, all of my kids LOVE them. And I love that the baby can even play with them and I don't have to worry about him choking on small pieces. They are super expensive but Amazon will often have good deals. We just got a set 40% off a few days ago.
legos, legos, legos and more legos!!!!!!!!!
I feel your pain!!! And of course the eldest son wants all the larger, more expensive kits!!!! lol
I know!!!! Legos are so expensive! And the ones he wants (pirate ship, deep sea exploration ship, deep sea base) are all $100 each! He really wants the star wars sand crawler. I had to veto that one - it's $300!!! For one lego toy! He can get 3 large ones for the price of that!
And wait until he wants the Death Star...$500!!! We vetoed that one!!