When you bounce your flash, you actually already made your flash off the camera AND you made the light source really big (the size of whatever the projection of the flash on the ceiling or wall) and diffused. Adding bounce card to your flash will only add direct light which is what you are trying to avoid. Pretty much if you can bounce it, bounce everything. Don't use a bounce card.
Now, if you put the flash off the camera, all you are doing is putting the light source from an angle (which can already be accomplished with bounced on camera flash). Your flash is still harsh. Sure, you can add umbrella or softbox but then bouncing on camera is a lot easier because you can use your TTL, you can do 2nd curtain, you can do HSS/FP, which a lot of trigger wont do.
The only advantage of off camera flash is when you cant really bounce (i.e. outdoor, dark wall/ceiling), or when you are trying to be creative with multiple flash guns. You also get more consistent result because when you bounce, the flash metering is doing it's own thing and you dont get consistent result (plus your bounce change all time). I hope that makes sense.
I just simply can NOT agree with this, AT ALL. First off, when one bounces a flash indoors using standard front-facing bounce methods, there's a very great tendency for the light to come raining almost straight down, which is what creates the lifeless and dull look in the dog pics. Using "something", "anything", to get just a little bit of flash going right at the subject to create a catchlight is often better than straight,plain, forward-facing bounce flash. Try a bent business car, or a plastic spoon, taped or rubber-banded to the flash, so that a little bit of the flash beam hits the card or spoon. This is a method for CLOSE-range shooting, as you were doing with the dog...this is a 1980's PJ trick--not for long throws, but for CLOSE-range, indoor bounce flash shot with the flash-in-the-hotshoe method. Like the two shots of the dog.
As far as getting "good light metering" with TTL bounce flash...uh...that might be one of the single biggest weaknesses Canon cameras have had for the past decade. STRAIGHT-AHEAD e-TTL-II flash is decent, although nothing to write home about. Note the qualifier-e-TTL Version II. Color-blind flash and color-blind ambient light metering is a recipe for bad through the lens flash regulation. Nikon has been ahead on color-aware flash and color-=aware ambient metering + distance for a long time. Some of the differing opinions on bounce flash and flash as a whole come out of the tremendously different ways that Canon and Nikon have developed their flash metering and flash-regulation concepts. before e-TTL-II was developed, Canon had a HUGE problem with TTL flash being overly-sensitive to the specific AF spot that was active. The shiny d-slr sensor and AA filter makes the pre-flash rather so-so in terms of reliablilty and repeatability...film simply worked "better".
In many ways, the old AUTO-Thyristor flash metering is better than e-TTl, E-TTL II, d-TTL, or Nikon i-TTL.. It always "depends".
One of the single BIGGEST problems you will run in to when bouncing a single speedlight is that the flash will NOT be powerful enough to expose the shot well enough if you are using the lower ISO ranges with "normal flash units". Using HIGH-ISO settings and bouncing the fl;ash is a technique that Dennis Reggie (sp?) is sort of famous for. As Keith stated in post 10, it can be difficult to separate the BS from the good stuff; his link to Neil's web site is a good,good link that's free of the BS. You can try adding "+" exposure compensation on the flash unit--but if the room is big, the aperture small, or the ISO low, or any combo, then all the "+_" compensation in the world will not give any more exposure if the flash is "topped out"...
Bounce flash can look fantastic, very good, okay, or bad; it largely depends on the skill of the photographer and how he/she uses the equipment and the location.