Hi Margaret,
Post processing of images is a very interesting topic with many diverse opinions. I also am a Canon user who has dabbled with both the Canon DPP software as well as Lightroom/Photoshop. I photograph only in RAW (not RAW+jpeg). Every method will result in slightly different images - for example the same image processed with DPP to produce a TIFF or JPEG image will be slightly different in colour tone that an image processed using Lightroom to produce a jpeg, even with colour calibration for the camera and the photo (e.g. using a colour munki colour card).

Using DPP is straight forward and there are some basic rules which can reduce the amount of time to process the images based on the ISO setting of the camera to reduce the overall noise. I did use this for several months but preferred not to generate a high resolution TIFF image for each RAW image I have.

I have opted to use Lightroom as my primary tool for post processing for the following reasons:
As I import the photos from the camera card to my laptop via Lightroom Import I apply
- camera calibration settings, sharpening (amount, radius, masking) and noise reduction (Luminous, chromatic) for images taken in good light conditions (ISO < 500) via a Develop Settings Preset
- Location and copyright data via a Metadata preset
Once imported into Lightroom I filter on the higher ISO settings to apply noise reduction settings that I deem reasonable starting points for that particular ISO setting.
I then delete unwanted images and apply adjustments to individual images that I decide to keep. This includes
Basic exposure settings are applied (as per other programs) such as exposure, highlights, whites, shadows and blacks.
Lightroom can be used to clone out simple distractions - a branch against a blue sky etc
It is only on rare occasions now that I export the photo to Photoshop and via layers and the selection tool apply different noise reduction to the background and to the bird which is the focus of the image, or do more that a simple cloning out of an unwanted branch.

I like the fact that in Lightroom I can create a virtual image to apply different cropping and/or exposure settings etc. - for example I apply a different crop for images I upload to Birdlife photography compared with home use where I tend to show them on a 16:9 ration TV.

Another main advantage that I see with Lightroom is that I use it extensively as my image library, with over 70,000 images with the ability to stack images and sort, rate etc easily.
Disadvantage is that the time to load a RAW image and apply the adjustments can be slow, depending upon your memory and processor speed.

My advice, as per an earlier response, look at the newsletters to for the articles on image processing, try them and then adopt the one that suits you the best.

Regards
David