You should know that they are discontinuing the TC29 models. I don't think this should stop you from buying one but you should be aware of it.
You should also be aware that the TC33D is being changed for 2004 and it will be called the TC33DA. They will be replacing the 7308 loader with the 14LA loader, which will have increased lift capacity. The 14LA also provides better visibility and it looks sharp. To help handle the increased loader capacity, the front axle will be redesigned. Finally, it will have the new style hood with the vertical head lights. It should be out somewhere between late fall 2003 and late spring 2004???
As far as I know, the TC30 will remain the same and keep the 7308 loader. Powerful little machine for the money but it is lacking some of the options / features / refinements of the Boomers. It also has metal fenders/hood instead of plastic, which can be good or bad depending on your preference.
If you are new to tractors and mostly mowing and using the loader, then I would recommend Hydro. Hydro is very nice for mowing and loader work, especially if you are not familiar with tractors. You will find many people who agree with this and many people who disagree with this. It is an ongoing discussion and has occupied many threads. There are many die-hard gear fans out there and gear has come a long way with options like Synchronized Shuttle Shift (NH), Power Reverser (JD), FST (K) or GST (K). I have used something similar to a Power Reverser on a Case 580K and, as easy as it is, I would still prefer to use a Hydro for loader work and especially for mowing. With that said, you can save a $1000-$2000 by going with a gear.
If I were you, for 20+ acres, I would definitely look into the Class III Boomers (TC35D/TC40D) assuming you are set on NH. Others you could look at in this range would be the JD 4410/4510 or the Kubota
L3430/
L3830. These machines will enable the use of larger implements. For instance, an 84" finish mower, 84" rotary cutter, 80" Tiller, etc.
If you are set on the 29-33HP range, then I would definitely go with the TC33D or wait for the TC33DA, assuming you are also set on NH. Others in this HP range would be the JD 4210/4310 or the Kubota
B7800/
B2910/
L3130.
Please don't think I'm trying to steer you away from NH by mentioning other brands. I'm a big fan of NH machines and I have been drooling over them for weeks. I just thought you may want to explore the big three before sinking $20k+. Perhaps you already have.
If you don't have any good local NH dealers or if you are just looking for out-of-state NH dealers to save yourself from the 7.5% sales tax, then I would highly recommend talking with Scammon Tractor in ME or Corriher Implement in NC. My biased favorite is Scammon but both of these companies have been extremely responsive and helpful. With that said, I'm not sure if Scammon sells outside of their service territory so you would need to ask.
As with all advice, you get what you pay for and keep in mind that I'm in the same predicament as you are.
Whatever you decide, make sure you let us know and post many pictures.