I just went through the long arduous process Videre described (well thought out and I came to many of the same conclusions) when I picked up my second 100. Then after weeks of web searching I had a revelation that newest/cleanest/lowest mileage/most factory bells and whistles was not the right approach for me. I decided to just buy another early model that I was familiar with and throw the difference of my budgeted $ into mods. For MY intended use it was the logical position for me to settle on. I ended up finding another '99 that already had several mods I wanted done. It's a perfect fit and a great starting point on what I wanted to build that 100 up to.
Land Cruiser shopping has a few interesting dynamics. Intended use can vary pretty wildly from person to person so that's an obvious given. The 100 is probably the series that is seeing the most attention right now. Be that from Mall Cruiser types to Moab types. Also lots of seasoned 80 guys seeing that the 100 can go almost anywhere it fits. Tons of 4Runner guys with growing families. Finally there are many people seeing earlier 100's falling within reach with all types of intended uses.
Timeframe and locale also play another role. There is currently ONE Land Cruiser within 300 miles of me on AutoTrader that are around the ~05MY and $25-28k. Let me tell you those tempting $20k '05s on AutoTrader are some real jewels too...

Showed me very quickly that used car dealers have many ways to get rustbuckets & wrecked trucks with clean carfaxes... Patience is huge with Land Cruiser shopping, and having your $ ready when one pops up is just as important.
Happy Ending: When the one that fit me popped up it was 600+mi away and a 10hr drive one way. I initially IM'd the owner on 'Mud on a Wednesday night (IIRC), boarded a jet that Sunday morning to Mississippi and drove it back to South Carolina that same day. The seller already had another interested party ready to come from the east coast for it if I fell through... Be quick, be prepared, be thorough!