What Amiga do you have at the moment?
You have to ask yourself what will an A2000 offer me over an A500 / 1200?
My personal opinion is "next to nothing".
There are much better Amiga things to spend your well earned dosh on than an A2000.
Like what?
If you have an Amiga A500 then the best buy is a GVP HD8+ with 8 Meg Fast RAM. (GVP A530 if you can afford one)
If you have an Amiga A600 the best buys are a 2.5" IDE disk + PCMCIA Ethernet card + 1Mbyte Trap door.
If you have an Amiga A1200 then it's again 2.5" IDE disk, PCMCIA Ethernet card + Trap Door fast RAM / Accelerator.
Buying a Big Box Amiga 2000 will only give you a better Amiga experience IF you buy a Zorro GFX card and to use one you need an accelerator and a SCSI controller + Hard drive! Before you know it you've spent much more than you expected!