The basics - a simple bitter

I've been homebrewing for about six months now, and I feel like I'm starting to notice subtle differences in taste associated with different ingredients, but I think it would serve me well to make a nice simple beer that will help me say "This is how EKG or Cascade hops taste" and "These are the flavors that Nottingham yeast imparts" I tried to do some searching, but I know a few months ago this concept was discussed.

Last brew (A Sierra Nevada Pale Ale clone) was the first time I went to the LBHS with a recipe list and constructed my "own" kit. I'm not at the point of all grain, so I'm slightly limited to extract with steeping grains. But I still think I can make a decent simple beer and also gain some more knowledge about the ingredients.

I saw a recipe for an "English Pub Ale"
6 lbs. Gold Malt Extract
2 oz. Northern Brewer bittering hops
1 oz. Fuggles aroma hops
1 oz. Goldings aroma hops
1/2 lb. Crystal 10 L
1/2 lb. Carapils grain blend
Wyeast 1968 ESB Ale yeast

That sounds great, but I think I would like to stick to something even more basic. Could Goldings be used as the sole hops? Bittering and aroma? Is there a better type of hops that can serve both purposes? I know that I love the aroma and flavor of Cascade hops, but I would like to branch out and try something new.

6lbs. of Light DME
1lb of Crystal 10L
1 oz. Goldings bittering hops
1 oz. Goldings aroma hops
1 oz. Goldings aroma hops
US-05 dry ale yeast

Is that too simple? Would that taste terrible? I love complex beers, but like I mentioned - at this point I don't know which ingredients are supplying which flavors and I think it might help me when I come to create my own recipes.

That looks fine to me. There's absolutely nothing wrong with using just one kind of hop. I generally prefer the complexity you get from mixing different flavors, but this certainly sounds like a good way of identifying what tastes come from each ingredient.

Another good technique is just to taste the raw ingredients. Hops and malt both come out tasting pretty similar to how they taste in their original form. It's just a shame that hops in the store are all sealed up in bags, so you can't smell them all before purchasing!

The main thing to watch is your bittering levels. Goldings are typically around 5.5%, so less bitter than something like Northern Brewer (which is usually around 8%). So if you are substituting these into a recipe that originally called for Northern Brewer, you may need to up the quantities to compensate.

Paying proper attention to hop bitterness levels is one of the things that recently improved my brewing by a significant amount. Up until then I'd been ignoring all the numbers, and just thinking "hey, I got an ounce of the same variety the recipe specified: that'll be fine, right?". Turns out, not so much. I realized the folly of my ways after one brew came out way too bland and lacking in bitterness. Now I'm paying attention to the AA levels of the actual hops I bought, and entering this into Beer Smith to estimate the final IBU (nice thing about that is it also accounts for how much malt you are using, which lowers hop utilization, and whether you are doing a late extract addition). This gives me a much more precise way to control how much hop bitterness I want to end up with.

i would use s-04 instead of s-05 for an english ale. it would be a lot more similar to the wyeast 1968 in the original recipe.