Hello, Willian;
I have some suggestions, but I think it would be easier to post about which ones are NOT a good suggestion. To be honest, as you may read from others, there is no preferable LED calculator (meaning you are talking about HP units), it's only a matter of choice and need. Please, have a look here for further details.
If you need a financial calculator, the best price X performance ratio is the HP38C (or HP38E, without continuous memory). There are others, mainly collectors' "driven", as the Woodstocks HP22 and HP27, but they are somehow expensive. Not to mention the HP80, HP70 and the Topcat financial series!
If you want a scientific model, there are many good units. Some of the most "powerful" are the HP34C and HP67. The HP67 is a Woodstock wearing Classic clothes (I'll be flamed for this...) and it has all features available with the HP97 except for the printing "facilities" and the desktop design, meaning 26 storage registers, 224 program steps and a huge amount of functions and programmable resources. The HP34C goes a bit further with the internal resources, mainly continuous memory, numerical integration and SOLVE, but offers no external device (card reader, printer). I own an HP34C and an HP97, and I have much fun using any of them. They are great calculators.
Other great scientific models are the HP65 and the HP95C, but this last one is the "cream of the top", allowed only to a few dedicated collectors, Dave Hicks included. Some not-so-expensive units are the HP33C/E, HP32E and HP31E.
Aha! Many of you thought I'd not mention the Woodstocks, didn't you? I left them as the last ones because they must be mentioned and remembered (I personally take them as too good to be true): the HP21, HP25/25C and HP19C/29C (the HP19C is the printable version of the HP19C and is categorized as a Sting, not a Woodstock). To these ones I have just a few words: try them out! Seeing is believing.
Any model that's not been included here was left behind because I did not remember them... Sorry :(
Anyone else?
Best regards.
Luiz (Brazil)
(P.S. - I would also include the TI58C and TI59, because they both are formidable calculators as well. Let's be honest...)
Edited: 8 Dec 2003, 11:34 p.m.