If your willing to settle for less than an Arranger you might want to check out the Roland Fantom S/88. It has Sampling, Expansion Bays, in other words it is a Full blown Workstation. It would be ideal for making Jazz, techno, etc. tunes. It only has 64 note Polyphony but they might make an expansion card one day that will increase the polyphony much like how Yamaha made one for the 9000Pro to increase its Polyphony. PS: If you Sample your loops and sounds that will free up additional Polyphony too. If you must have an Arranger don't forget to check out the new gear at Summer NAMM 2003. It starts next month, (July 18-20). News about NAMM can be found here:
http://www.harmony-central.com/ PS: If your parents have the dough, maybe you can talk them into getting you one sooner. Christmas is not too far away you know.

Best regards,
Mike