Man, get yourself a Roland MC-808 Then get a inexpensive midi controller. You can get an 808 now for less than $800!!! This puppy has a good soundset (fully editable too) sampler (with slice/auto chop), 128 note poly. 16 track sequencer (built in). An MC-808 and inexpensive midi controller will run you $1,000 As far as monitors..., man there are quite a few nice affordable units out there like the behringer MS16's (they sell for under $60.00)

Here's some links:

Roland MC-808 (groove box) http://rolandus.com/products/productdetails.aspx?ObjectId=766&ParentId=84

Here's the Behringer MS16's (I have these) http://www.zzounds.com/item--BEHMS16

Sure you can go software down the line, but that too can get costly!!! You're always gonna be wanting more softsynths, more RAM for the computer, blah, blah... If you want a good hardware set up you can't go wrong with the MC-808 The 808 will beat the Juno-G hands down for what you want to do (it's designed for it)

Best Regards,
Squeak