Investment in digital hardware like converters is money down the drain, in the relatively short term.
Investment in a quality preamp will retain resale value for years. A preamp makes a bigger difference to your sound than converters. A good preamp will also make cheap mics sound their best.
Do you need to record more than two channels at once? If not, an M-Audio Audiophile 192 would get you into some respectable low noise converters with balanced outputs, and is Protools compatible if that's worth anything to you.
With the money saved, you could look at a Rupert Neve Portico 5012
www.rupertneve.com
For a small investment you could be running a 'Tools studio with Neve preamps, and hold your head high with all the other pro-wannabe's.
I think investment in the other stuff would have very little resale value, and nothing to impress future clients.