I have all three. Tough choice.
LOTR is probably the best of the three and the one I would recommend, but there are pluses to the others.
LOTR has the best code. The way the code is written really makes you feel like you are on a journey. The layout is fantastic and I love the ring shot. Some complain about long ball times, but you can make adjustments to increase the difficulty if you like. I've left mine on medium. I don't mind a longer game every now and again. Plus with LOTR, you really need a longer game to experience it all. Destroying the ring is a heart stopper the first time you do it. If you haven't done it, you will understand what I mean when you do . I love the game and have owned it for years. I bought HUO and that's what I would recommend. HUO tends to keep it's value.
If you are going for value, hard to beat TSPP. It's fully featured with fantastic code tied nicely to the show. It's got so much stuff on the playfields (!), I'm sure it would be priced as an LE if it were made today. Great game that to me is under valued. There is so much to love about this game. I love the mode where the flipper reverse. I love the fully functional mini-playfield with a shot to a third(1) level - the couch. I love how the shots related to the mode, for example Homers Day. First shot the pop bumpers that represent the power plant, then it's off to Moe's so shot the right ramp, after Moe's Homer likes to head home so you need to shot the garage, then up to the sofa to end Homer's day. Alot of thought went into the game and it really shows. Look for a HUO and grab it.
I love ST, but you mention not wanting to loss money. If you buy NIB, chances are you will loss money when it comes time to sell. If you decide ST, think HUO. I bought a HUO and got a ton of mods included. I figured I tire of the game in a year or so. Bought it just over a year ago and still love it. In fact, I actually play it more than the others. The flow is super smooth. One complaint I have read is the modes essentially have you chasing colours. I can see that point, but there is so much more going on...you can combo shots for increased points, earn bronze, silver, and gold medals in tier 1 modes which earns points in bonus and points in mini wizard mode, there are a few multiballs you can start during a mode, there is the opportunity to double points by shooting the warp ramp, one of the Vengeance modes awards 10% of your score, and I'm sure there is more I've forgetting. It's an absolute blast to play especially with a shaker motor attached.
I really enjoy all three games and don't think you will go wrong with any.
Good luck!