Sure, here ya go:
There are a number of Toto toilets in a variety of styles and configurations, all of which flush well. The variations from one to another can be regarding such things as (a) gallonage per flush (dual-flush, 1.28, 1.6 or the latest 1.0 gallons per flush); (b) bowl rinse; (c) height; (d) ability to mount on other than a standard 12" rough-in; (e) aesthetics (and I put one-piece in that category, although there are some minor functional advantages and disadvantages; I also put "skirted" vs "nonskirted" in that category, particularly if you have a standard rough-in, because the skirted Totos can generally be mounted on other than a 12" rough-in but otherwise the skirt is purely aesthetic or maybe a teensy bit functional -- easier to dust, I guess).
Easy to recommend:
Toto Original Drake CST744S or CST744E. This is a high-quality workhorse toilet and a very fine value. We have two of them. The "S" is 1.6gpf, the "E" is 1.28 gpf. You might get a smidge more bowl rinse or flush power in the 1.6 over the newer 1.28, but most people couldn't tell the difference in performance if you put them side by side -- they both use the same bowl, just one has a tank that dispenses a little more water in the flush than the other. If you have "Watersense" rebates from your water company, then you would be eligible for a rebate with the E but not the S. If you want ADA Height, then its CST744SL or CST744EL. This toilet has a little less bowl wash than the double-cyclone, but we haven't had any noticeable issues with it. And it's a legendary flush. Simple guts, easy to replace or get repair parts basically anywhere.
Toto Drake II CST454CEFG. This is a more modern looking toilet with some bells and whistles included standard at an affordable price. It is 1.28GPF (the "E"), it has Double-Cyclone Bowl Rinse (which I guess you are familiar with; the "C"). It is ADA Height (the "F"), and it has the non-stick Sanagloss finish in the bowl(the "G"), which helps with cleaning and resistance to discoloration, although nothing's perfect and you can't use Comet on it, just dish soap or liquid bowl cleaner. Also uses basic, generic parts.
You asked about what is called the "Drake II 1G", which is a version of the Drake II that only uses 1 gallon per flush. It has a different-looking tank, and otherwise has the same features as the Drake II (CFG), but only dispenses 1 gallon per flush, and uses a non-generic mechanism to do that, so you can't just change the flapper when it wears out, you need to get the rubber seal from Toto. Not a huge deal, just something to be aware of. It is model CST454CUFG. From what I can see, it's selling okay, and flushes pretty well given what it is.
The Ultramax II is a wonderful toilet. We have a skirted version called the Carlyle II (so we could mount it on a 10" rough-in). Looks great. It's a clean, modern look; although we have installed it in a period-style bathroom, it meshes perfectly. It has the same CEFG features mentioned above. It's a bit more money is all. Its flush capability would be similar to the Drake II. MS604114CEFG It comes with a nice toto SS114 seat included. (Generally, the toto one-pieces include a seat, with the two-piece, you get your own seat. You can uses a Toto seat or any major brand of seat, although the Toto seat is a nice one and matches the color perfectly.)
As to sources, there is a reflexive avoidance on here of references to other-than-brick-and-mortar merchants, so we don't discuss it. The best way to find a deal is to open the yellow pages to plumbing supply. Write down the phone numbers of at least 7 of them, regardless of whether their ad says they sell Toto, and call them for prices. You will find a crazy variance from place to place. The best way to do it is to write down the exact model number and color you want, and give it to them and ask for a price quote on THAT, and that you're ready to buy today if the price is fair. Call all 7, regardless of what you hear, and then look at the prices in light of the promised availability, distance from you, additional services (i.e. home delivery) etc. Some Totos are also available by order through HD, although the selection is poor and the prices are definitively not as good as I could find at some plumbing supply places (but not others). You can see some of their selection by looking on their web site -- just search on "toto". There is a bigger selection available to order in the store, but some info is wrong, like the basic drake Ii is not "discontinued"; its a best seller everywhere. And we don't recommend having toilets shipped directly to your home by HD because their packing isn't reported to be the best. And I don't recommend the carusoe toilet they sell at HD. It doesnt have the big trap and 3 inch flush valve. Thats the only toto I would actively discourage.
Any other questions, just let us know!!