I think the general consensus is that the 603 is a very decent mic (I own a pair and like them on acoustic guitar and drum overheads), but the 2001 is a bit of a stinker. Although I've never used the 2001, I suspect the reason they package the 2001 with the 603 is that they can't sell it by itself. I'm sure you could find some use for the 2001, but you'd probably be better off getting another of the inexpensive large condensers (SP B1, MXL V67, etc.) instead.
I did a quick test drive with an MXL 2001 running through a Mackie Board with the mighty VLZ pre using Sennheiser HD 280 pros Headphones.
Now being a big lunged horn player, I can pump out some major vocal sound.
Singing into the MXL 2001 was like singing into a pillow with your face in the pillow. Whatever you put into the mic stays there and becomes flat and lifeless. Flat and Lifeless is what came out.
BG/HSG
What about RODE mics since you are from Australia (I think?)
There are a lot of folks who like the 603.
I'm not sure what your recording system is, what your recording needs are or what your budget is, but I'd recommend you spend your available $$ on just one decent Large Diaphragm Condensor (LDC).
If you can pick up a decent used RODE NT2, that would be an excellent mic to start with. The new RODE NT2A would be another nice on to get if it is in your price range.
I am assuming you can get these for a little less money since they are assembled in Australia.
Also check out this thread: http://www.homerecording.com/bbs/showthread.php?t=183823
BG/HSG
I've heard the 2001 talked about a lot. From what I see I've gotten about 3 guys who like it and think its alright for some vocals and maaayybbe acoustic. I've also seen about 2000 who absolutely hate it. I don't personally know about the mic, I've never used one because of the nearly all negative response on every post i've seen. I do happen to have a pair of 603s. They are the best mics I've used so far on acoustic guitar. They are great as overheads in cases with studio cymbals or ones that don't let out an excessive high end. They are a bit too bright for guitar cabs, but when mixed with a 57 and a KSM 27 its the best representation of the actual cab sound i've found, Depending on where you mic it. I've heard that they sound pretty damn good on toms too, but I've never had the chance yet to use them (I should get around to trying that). The great thing about them is that they are relatively flat with just a bit of hyped high end. In my case this annoys my as I am on a search for some flat mics. I've got to give them a great review though, especially for the price. I'd get them.
On an other note, I only here good things about the v67, and I've heard enough good that I actually am thinking about buying one myself. I don't have that much money now and its hard to decide if I want that or to save a bit more for a v69. Then again I gotta get me some KEL HM-1s first.