Since you have a 17BII, you can certainly try out RPN since this calculator can operate either RPN or Algebraic.
What exactly are you looking for in a calculator?
If you want all the bells and wistles (even for the sake of HAVING THEM, many of us are in this catagory), Buy the Hp49G (ok, it doesn't have eq lib). It is actually much cheaper than a 48GX if you later buy a RAM card.
Also the 49G does have algebraic input.
Now for some bargain tips:
THESE are not for the hard core HP RPN user, but since you have indicated that you use Algebraic on your Hp17bII, you may also consider these next three calculators.
1st to consider may be an Hp19bII. It is not a big step up and costs almost as much as a discounted 49G, but it is exactly the same as your 17BII for operation, but also has Trig, notepad, and units converstions. All nice extras and you wouldn't have to open the manual to use this calc like a pro.
2nd is a Graphics; Hp38G, Cheap (certainly less than $50, and maybe less than $25) Still has the Hp quality feel, is Algebraic only, but has plenty of MATH functions. Sadly doesn't offer any other features such as a Finance solver or units conversions. Has only 32K.
3rd is an Hp 39G, a near look alike of the 49G, but algebraic only without CAS or RPN. Also without units conversions or a built in Finance solver. Very similiar to the Hp38, but with added functions and 240K RAM. List price is $80 and are usually sold for much less.
Both the 38 and 39 have Hp solve so you could add nearly any function you want easily or program in you functions with Basic.
If you use or like RPN, the last two calculators are NOT for you. Also the solver on the Hp38 & 39 can only use a single letter name of 27 available (A-Z & theta).
Since you indicate you like your Hp17bII, play with a 39 or 49 before you buy either, since they FEEL different from the older Hp calculators. In fact they FEEL different from each other. I don't mind the 49 since its rubber feels much stiffer and has some tactile feedback vs the 39 feels like a spongy rubber keyboard. Neither feels as good to ME as a 48 or 38.