There's not a WHOLE lot on the list that I really HAVE to see. Hopefully the additions will be solid. One group of bands/djs that might be in conflict with each other is Bassnectar, STS9, Pretty Lights, and Girl Talk. In 2009 I had never heard of Pretty Lights and ended up at Girl Talk. I've seen Pretty Lights twice since and will definitely go with them over Girl Talk. Bassnectar and STS9 is a very very tough choice for me though. If they are conflicting it'll be hard to choose. Bassnectar I've only seen once and it was mind blowing. STS9 I've seen several times and it too is mind blowing. However I've seen Bassnectar more recent and have the STS9 itch. I guess if anything I would catch part of each show but I hate doing it. So if these conflicts arise I guess it would be a tie between Bassnectar and STS9. Bassnectar/STS9 > Pretty Lights > Girl Talk
In regards to the OP, you mentioned you'd only seen Bassnectar once. Keep in mind that the second time you see him is WAY less impressive than the first time. He's got an awesome live show but a rather limited bag of tricks. Still a really fun time, but definitely loses that "holy shiz" factor after you've seen him once.