I'd say plan ahead now. Where are you headed? What is your goal?
I have a PreSonus MP20 that I put BurrBrown opamps in. It was my first "good" or step up preamp from my Mackie 24-8. I added an ISA One (though I wish I'd gotten one with the AD card and plan to add that ASAP). Recently, I bought a Warm Audio WA76 and Tonebeast, and feel like I have moved way closer to my goal! I think one of the best options of the Tonebeast is you can swap out one of the opamps! I just added a John Hardy 990C+ (replacing the X18 Jensen one) and the fact that you can take the Tonebeast up from where it is, already, is a no brainer! I haven't seen anything about anyone using the Seventh Cirlce Quad 8, the Trident one, nor the Ticha, but am hoping that will change the more the TB-12 filter out into "studio world"!
http://www.warmaudio.com/products/tb12-tone-shaping-microphone-preamp/ I'd love to aim for the new Millenia's and then "down the road, a bit" Chandler and Great River. But I might try the Black Lion B173- $549. Those are my current "nicely rounded out" front end plan. Of course I have to upgrade my I/O, but that is an exciting proposition!
Get the best conversion, I/O, preamp, and mic you can afford NOW and work on your space. I bought a ton of stuff for my last "big" set up(home studio for hire), hoping to impress clients with my gear list. What a waste of time that was! Impress yourself and your results will inspire you (and your clients, if you do that).
Hmmm, well I can certainly tell the difference between decaf and regular, this morning! LOL
Michael