I'm not big into Gouda (more a Leyden guy), but now and then I get a couple of Baby Goudas added to my iGourmet order. I notice they have a LOT of choices however and thought their list might be of interest to you. If you've never bought from them, be assured they are a top-notch company.
Aged gouda with butterscotch-like, crunchy tryrosine crystallization is my favorite cheese. Don't confuse it with the mass-produced, wax-covered, mild (or smoked) cheese your mom may have bought at the supermarket.
Also take a look at Mimolette
Less intense is the goat Ballerina and sheep Ewephoria.
Lots of good suggestions here too:
I like the aged Dutch Goudas a great deal! I haven't run across a domestic gouda that develops the depth of Butterscotch Diadactyl nuttiness as a great 3, 5, or even 7 year!
On the other hand, the Midwest abounds with amazing young-ish to middle aged goudas that are really complex and full of character- I hope to see them aged further!
Fleur de Terre from Traders Point Creamery- Natural rind, organic grassfed milk- tangy, supple, earthy
Frisian Farms Gouda- farmstead, super complex buttery grassy notes
Feather Ridge from Ludwig Farmstead creamery- really a fontina, but tangy, nutty, almost meaty
And my all time go-to domestic gouda: Emmi-Roth Kase VanGogh Gouda- creamy, caramelly, "if each slice of American Cheese were lovingly made by hand, it might taste this good" perfect for kids of all ages.
A 3-yr aged firm Gouda is on my list of favorites. A little less expensive, but good, is Beemster Classic Gouda, aged 18 months.
They also make a very good Goat Gouda that becomes very complex as it ages.