You have a local problem. That is not unusual.
You should look into solving it since there aren't "tons of problems" with either of the two pieces of hardware you have. Since the MBP works at work, I'd start with the Extreme. Wipe it clean and reinstall the firmware updates, change the protocols/frequencies, etc. I have seen environmental situations like these that were solved by going to "n" at 5GHz. Here is a link to something that resolved after much effort and the problem was totally environmental, although I do not have a clue what it was to this day, but I fixed it:
http://discussions.apple.com/message.jspa?messageID=6553680#6553680
I just couldn't blame the equipment because once you took it out of there it worked flawlessly. I was using the same MBP as yours at the time, btw. Another time, microsurges at the electrical outlet where the Airport and the cable modem were connected created internet and network havoc. It was discovered accidentally as I noticed that the problem, one time, surfaced when someone fired up a vacuum cleaner and my connection went west. Sometimes you have to think outside the box.
Food for thought.