I've tried several things as well, including the use of a swinglens panoramic camera and using an ultra wide angle lens.
Here's a short tip of mine about panoramas: http://robertdfeinman.com/tips/tip6.html
and here's another about super wide angles: http://robertdfeinman.com/tips/tip23.html
I would say the best way to get to see differently is to change your point of view. This requires no new equipment, just get close to the ground or shoot from above, or tilt the camera or do anything else to break out of the eyelevel vantage point.
Another thing to try is changing your subject matter. If you are shy then try to approach people on the street, if you usually shoot family or friends then try architecture, etc.
In spite of what the photo press likes to say, there are no right ways to do things, only conventional. If it speaks to you, its right for you... Policies not Politics ---- Daily Landscape
But with the Holga I hope to remind myself of how it was to have a fresh eye to taking photos and bring that back into my digital shots.
Thanks for the links. Ad astra per aspera
If you like medium format I would suggest looking at a used Yashicamat or Rollei. I see a Yashica on US ebay at the moment for $33. You get the nice negative, the ability to see what you are shooting and your choice of waist level or eye level shooting. You can even put on closeup lenses.
Using the Holga may be fun, but at some moment you actually might want the picture to come out properly. One can always blur a sharp picture or do other manipulation, especially if you scan the film and make edits digitally, but you are stuck going the other way.
In the mean time, just enjoy the camera... Policies not Politics ---- Daily Landscape
Here's a site which lists the ages of various models: http://www.siufai.dds.nl/Rollei_History.htm
So cheap Rollei's may be old Rollei's. The Rolleiflex is a better camera than the Rolleicord, but only from an operational point of view. Stay away from the various automatic models, they didn't work well.
Yashica's are probably much younger. In addition you can keep your eye on Mamiyaflex which even has interchangeable lenses. It's a lot bulkier though.
There are even some current cameras in production; the Seagull from China is inexpensive even new. People who use larger formats tend to become passionate about this.
I see there are a number of web sites devoted to the subject, you might poke around and ask some questions. Try this to start: http://photo.net/bboard/forum?topic_id=35 Policies not Politics ---- Daily Landscape