Hi David,
It's kind of a case of, beauty is in the eye of the beholder. The best thing to do is read every referrence that you can find on Lugers before you even begin to collect. Eventually you'll find the variation that interests you most.
The books, are in many cases, nearly half the cost of a decent Luger. So, if you have a good library in your town, check to see what they have. If you can find Jan Still's books? They would be hard to beat to start off with. There are several others, such as "Lugers at Random" by Kenyon which is dated and with inaccuracies , but is a good photo referrence. "Luger Tips" by Michael Reese is also a beginner's referrence, and which will give you an idea of variations.
"An Excellent Luger Collection" is hard to pin down. Quality and rarity is better than quantity in my opinion. Find what interests you and focus on that variation.
The least expensive "sleepers", in the opinion of many collectors are VOPO's and Russian captures. They aren't pretty, but can still be had at somewhat reasonable prices. Many believe that they will soon become their own catagory as collectable Lugers.
I see that you are in Virginia. Go to the Chantilly gun shows. Several respected members of this, and Jan Still's forum frequent that show. Some have tables and are willing to help new collectors. If you should run into a long lanky dude who goes by George Anderson? Hang on to your wallet and count your fingers after he shakes your hand. He'll be with a guy named Tom Armstrong who's also a bit on the shady side.
One final piece of advice is, don't buy until you know what you are buying. It's very easy to get burnt by boosted (faked) Lugers.
Welcome to the forum.
Ron