Out of the speakers that you have mentioned, I have the 4410 Studio Monitors. These are one of only two pair of speakers that I have purchased new. I cannot imagine ever giving them up. I originally powered them with an Alesis RA100 reference amplifier and the sound was very accurate, which I like. Since restoring them, including some grill repairs and replacing the surrounds, I have been using them as the mains in my home theater. They really excel in this role.
They are very sensitive to the amplifiers that are driving them. The Alesis sounded great, but I preferred the overall sound of the JVC receiver I was using for my home theater. This past weekend, I picked up a Panasonic receiver to go along with my plasma tv and bluray - the components coordinate better, especially the remotes. I have been tuning/tweeking the receiver to go with the JBLs, but I am not quite there yet. The surround effects are excellent, and the stereo imaging/soundstage are really good, too. However, the highs are overpronounced, which translates into shrill with the titanium tweeters. I suppose I'll dial them back a bit tonight.
Your L100T3 have the best crossover out of the L series, so that is a plus. I do like the smaller size of my monitors, but many people contend the bigger speakers sound a bit better for home use. My monitors cannot be beat for near or mid field monitoring, though. I love to park a chair between them and toe them in - it is just wonderful, especially with a good recording. I have compared these to Klipsch KP301,
Bozak 302a, Norman Laboratories Model 10a, Epi A120, EV Sentry 100A, Frazier Monte Carlo at length, and the JBLs are still king. I do have them in a compromised role at this time, but they pull this duty with aplomb. I had the big Klipsch in the HT mains for awhile, but they just couldn't blend or create the wide soundstage for movies like the JBLs. I will listen to Pandora, Last FM, cable music, etc. and really like the sound. Next, I will hook up an SACD player to the Panasonic and see how that works with my JBLs. I have a JBL center, along with 4 smaller JBL surround speakers in the ceiling corners. An M&K subwoofer fills in the bottom nicely. The 4410 monitors really pulled it all together, though.
FWIW, the big Klipsch are very, very close in comparison with the JBLs - horn dynamics, big 15" woofer. By close, I mean in terms of quality performance - the sound is very different. I am currently running them actively biamped as a stereo system in the bedroom. I give up very little to the full HT system when playing Hi Def movies in the bedroom, running stereo sound through the Klipsch.
For pure stereo music, I love my Bozaks with rebuilt/modified crossovers. They love to play my album collection. Again, these are a very big departure from either the Klipsch or the JBLs.
What I am getting at is you may want to expand a bit - other speakers are very intriguing. However, you really can't go wrong with two pairs of JBLs.