So let me put this in the proper perspective for you.
1. You need a fast computer with a minimum of 16gig's of ram with an Intel processor, preferably a Core I7 processor. Hers why:
Computers DAW's need the memory and CPU power to process your effects, reverb, EQs, automation, VST's, VSTI's etc.. even if your using outboard gear, eventualy it will end up in your computer. A lot of folks try to make music with laptops or workstations not built to make music. That usually ends up giving them the wrong impression about working on a computer. So i would say, invest in your computer first.
2. The MPC 2500 is a great rig. I love it. I love the sound, the compressor and EQ as well. There is nothing like it. However, even with all of the things that make
the MPC 1000, 2500, etc.. great its not without its limitations. The MPC cant keep up with the new gear such as the Resonance, MPC touch and NI Machine as far as new features and faster workflow go. But that does not mean the MPC cant carve out its own space in your studio.
2a. I like to re-sample my tracks through the MPC for that analog compression warmth. And if its not the whole track its the drums. This is what gives me and edge in the area of sound engineering and not sounding like i just threw some sounds in a box and made a beat. So there are certainly good reasons for keeping the MPC 2500 around even if its not the center of the studio.
2b. Don't forget about the midi input and outputs, especially if you have keyboards like a motif. Using the MPC to manage midi connections to you computer just makes sense. Especially if you have someone come in the the studio who plays keys... Just let them play and boom, you have the midi notes right there in the MPC already quantized.
Just some examples on what i do.
3. I know there are high quality VST that emulate analog compression and even tube compression. But there is nothing like the real thing if you have it.
4. Technology is evolving. The best thing to do is to move with it. Be flexible. Work it into your processes because if you don't you'll find yourself needing to make drastic changes all at once and that can be costly.