1. Click Options->Library & Folders->Manage Library Fields
2. Click Add New Field
3. Fill out the following fields:
Name: Date Acquired
Display: Date Acquired
Data Type: Date
Relational: Not Relational
Edit Type: Standard
Save in file tags: Checked
4. Click OK.
You now have a new field called Date Acquired, which you can set for any of your files.
5. Tag some music files, make sure the Date Acquired field is visible, and fill it in with the date of your choice.
6. If you want this to really work properly, you need to fill out the Date Acquired field for all your music files.
7. Go to the recent albums view that you referred to in your original post, and change the sorting order:
Click the drop down arrow at the top of the tab, and click:
Sort by->Date Acquired
Your view will now be sorted based on the date information you input into your new field. This info will never change unless you manually change it. It will be saved in the tags, so even if you remove the files from the library and reimport, the Acquired Date (and thus the sort order) will be maintained.
When you acquire new albums, fill out the date as part of your import process.
That's it!