Well the obvious answer is yes, the sale of used games is a problem for the game makers. They're not seeing any additional revenue from the resale of their game.
The not-so obvious answer is that used game sales have the potential to be a huge money maker for developers. Case in point: I bought Assassin's Creed used (though not from GameStop...I have my standards :p). I loved it. Even now, I pop it back in to do an assassination or two. And because I enjoyed it so much, I'm buying Assassin's Creed 2 on launch day. Bam, $60 that they wouldn't have gotten from me otherwise. 

There's also DLC. Let's say Assassin's Creed had new missions available to download. I would gladly drop some cash on extending the game. Again, money they wouldn't have gotten from me before. 

The best thing would be to look at it as if used games are a gateway into any future properties from the developer. And I'm spent.

Melee weapons. A necessary part of any action game. Whether to supplement hand-to-hand attacks, or as a last ditch effort to protect yourself when you are out of ammo, they are an intrical part of gaming. Most games settle for an ordinary knife or some sort of blade which is okay I suppose, especially if it's a katana. But then there are those rare games that go way above and beyond the call of duty, and include the Holy Grail of melee weapons...

I, of course, am refering to the chainsaw.

I was introduced to the blessed instrument of motorized cerration, like most gamers, by Doom. At first I was hesitant to even try using it. It was only a melee weapon, and I had shotguns, rocket launchers, and BFG9000s in my arsenal. It was in a fit of daring (okay, boredom) that I decided to see what it would do. Imagine my glee at the pixelized carnage that I wrought on the first pink demon I came across.

I admit, i giggled. But it was a maniacal giggle, like that of an evil genius who stumbled upon the tool that would finally destroy James Bond. Definitely NOT like a schoolgirl on a sugar rush at a Backstreet Boys concert.

Anywho, having found a new obsession, I went on an unholy rampage the likes of which Hell had never seen before. I tried (and failed) multiple times to complete the game using only the chainsaw. This continued until I realized that Doom kind of sucked, but the visceral feeling of flesh rending stayed with me.

Years passed. I played many a game in that time span, and eventually I had forgotten about the noble chainsaw. Sure, Capcom gave me a tease in Resident Evil 4, but it's hard to enjoy a chainsaw when it's being used in separating YOUR avatar's head from his body. As I cursed Capcom's name at this cruel twist of fate, I didn't realize that they would be the one's to reunite me with my favorite tool of torso truncation.

They gave me Dead Rising. A world that had long ago been lost to me reopened. The giggle returned. The chainsaw was back. And the game was polite enough to provide me with a complimentery Acheivement to unleash my chainsaw terror upon. I completed the "Zombie Hunter" Achievement using only a chainsaw, using other weapons only when I had to.

Having completed this, I prepared myself for another long span of time before another game would make use of the chainsaw. I didn't have to wait long. I found Gears of War, and I realized, we are in the midst of a chainsaw renaissance!

Now, at this point, you're probably wondering one of two things. Either you're thinking that I need to get professional help before somebody gets hurt, or you're thinking, well, you're thinking I need to get professional help. But you have to agree, all games, past, present, and future, can benefit from having chainsaws in them. Seriously, think about this. Thanks to the PSP, and the various Arcade services on the next-gen systems, we are getting a lot of classic games re-released. How hard would it be to program in chainsaws? Picture the following awesomeness:

Cloud and his Buster Sword? Screw that. Cloud and his Buster Chainsaw!

"You, Jill, the Master of Unlocking...ah screw this, take this chainsaw and cut the damn door down."

"Pika-VROOM!" (Followed by sound of Squirtle being sliced to ribbons)

"They set us up the chainsaw!"

And the opportunities don't end there. For future games, get sponsored by companies like Stihl and Husqvarna. It's a win-win situation. The developers get more money to spend on the game, and we get chainsaws. Ooh, Chainsaw Juggling for the Wii! Game of the Year material, that would be.

So I think it's clear what must be done to raise the gaming medium to the next level. Chainsaws are the future as Capcom seems to realize (two chainsaws on a stick...attached to a motorcycle? 'Nuff said...). Feel free to drop ideas on the matter in the comments section. I must away to carve my way to the "Zombie Genocider" Achievement. See ya in the funny pages...