I'm using Audiograbber as my ripper and the FLAC utility to convert to FLAC. It's a two-step process but it's okay with me. I also use Album Art Fixer to find the album covers. I don't trust the online databases because a lot of the US discs have different tracks or different track orders to our CDs, so I name them myself. Here is a little tutorial for ripping cds (Spearmint: please note this is for MCE users, your process will be a lot simpler). This tute assumes you are running an HTPC and have a separate PC (in the study?) for doing this sort of general work, as I do. Whether they are networked or not is unimportant.
1. Install a ripper of your choice, FLAC utility, Album Art Fixer and the FLAC codec into Windows Media Player.
2. First, rip just a single track and convert to FLAC and see if WMP will play it. I remember I had some trouble here, and had to go into Tools-->Plug-ins-->Options-->Background and tick the FLAC box before it would work - can't remeber exactly but found this info online. Once you've got it to work, install the same codec in WMP on your HTPC and do the same steps. Test to prove the track plays in My Music.
3. Rip CD into .wav files.
4. Rename tracks as 01 - The Locomotion

. etc. You need to use two digits to maintain correct track order, or three digits if there are 100+ tracks on the album.
5. Drag and drop them into the FLAC window.
6. Tick 'Delete files after encode' (or similar). Go into Tag Conf and correctly label Artist, Album name and Genre. Click 'Encode'.
7. Transfer the songs to your backup store on your PC. I recommend creating a separate folder for each album, and make it an exact replica of how it will be stored on your HTPC.
8. Open WMP. Go to 'Library', down the bottom choose 'Add New Folder'. Browse to the new album folder you just created. WMP now updates. This is necessary for Album Art Fixer to work.
9. Open Album Art Fixer. Choose the new album from the drop-down list. Click 'Fix'. Make sure 'Google Search' is activated on this next screen. Choose the album cover of your choice (200x200 or 300x300). Click it once to preview it. Then right click-->Save As. Browse to the new album folder, name the file "Folder.jpg".
10. Close Album Art Fixer by clicking on all the 'X's in the corner. Otherwise it will try and 'update' your music library. This gave me all sorts of problems. DO NOT LET THE PROGRAM UPDATE YOUR LIBRARY!! Use it purely as a tool to find album art, and nothing more.
11. Browse to the new album folder. Make a copy of the Folder.jpg file and paste it into the same folder. Rename it AlbumArtSmall.jpg (Note: not sure what this actually does, but I think MCE likes it for some reason)
12. Copy this entire album folder into the mirror location on your HTPC.
13. Go to your HTPC, into My Music. You may find the new album appears, but not all the tracks are there. The rest will be in an "Unknown" album (should be the first on the album list). Find the "Unknown" album and play the first track. You should see the track number for a split second (e.g. 01 - track name) and then suddenly the track number will disappear and leave you with only the track name. Skip through each track until all tracks are 'fixed' in this fashion.
14. Exit My Music and then come back in. You should find the "Unknown" album has disappeared and your new album is now complete!
15. Click on the new album, then click Edit Info. Use your keyboard to enter the Album Artist, click Save. This is necessary for the artist to be registered in MCE's database.
16. Go back to your PC, open the Sonos software. Go to Music-->Update Music Library Now (or similar).
I omitted step 4.1, which is where I open each track in Cool Edit Pro and adjust the volume to my chosen level and adjust the start silence to nearly zero and the end silence to 3 seconds. But that's just my eccentricities running wild......
This process has worked for me every time but once so far, when for some reason MCE will not display the cover art for Green Day's 'International Superhits', yet the Sonos does using the exact same jpg file. Weird......

A few notes on Artists and Genres:
I decided to make my own Genres as follows:
50s, 60s, 70s, 80s, 90s, Classical, Musicals, Classic Albums.
This is because Pop/Rock is too broad for me, and covers too much of my collection. It makes it hard to browse if you have too many albums in one genre.
I decided to not put the artist name in the FLAC tag for albums containing various artists. This is because even though MCE will not register an artist if you skip step 15, the Sonos will. And I don't want my Artists menu to be clogged up by tons of artists with only one song. Instead for these albums I put the artist name in brackets after the track name in step 4.
Hope this helps somebody!