I'll list my top 5 that I don't own.
1. Obi-Wan AOTC
2. Maul full CS exclusive got it
3. Count Dooku (not Darth Tyranus) got it
4. Luke ESB
5. Vader ESB
If you don't own any yet, the easy to find versions I'd suggest:
1. Luke ANH
2. Obi-Wan ANH
3. Vader ANH
4. Luke ROTJ
5. Darth Tyranus
Of course I'm a bigger fan of the OT sabers, so my top 5 list may be a bit biased. ;)