Need steak advice

[bobman0330]

I'm looking for a really good steak.

Option A: Do it yourself
Step 1: The Meat
From what I hear, USDA prime, dry-aged NY strip is the way to go. Correct? How much should I be willing to pay for such a piece of meat? The Whole Foods near my house is charging 20/lb. Reasonable? If not, should I go for an inferior cut?

Step 2: The cooking
I live in an apartment, so I don't have access to a real grill. The best I can do is a gas oven. Is this a deal-breaker? If not, how do I go about the cooking? Please incorporate horseradish if at all possible. I prefer my meat as rare as possible, but I'd be willing to go all the way to medium if required.

Step 3: The sides
Somewhat off-topic, but does anyone have any good recipes for mashed potatoes. Possibly involving horseradish or garlic?

OR

Option B: Steakhouse
Anyone know any good, but reasonably priced steakhouses in the DC area. Any tips on ordering would be appreciated.