For quick and clean on bass, guitar or vocals, Focusrite Trakmaster with the digital card option. Vastly under-rated. I guess that's why Spike Stent and Madonna use one. You can easily pull a magnificent sound from one of these.
For portable, and digital, Roland MMP-2 (vastly under-rated). The in-built limiting tends to make these not only fool-proof, but almost dickhead-proof.
For quick and sweet on vocals, LANGEVIN or Manley.
For acoustic instruments, Avalon or Brent Averill (Neve).
You really can't recommend mic pres in isolation.
Mics and Mic pres and source material almost have to be considered as a functional pairing.
It doesn't make much sense to pull out one third of the following chain in isolation.
Source material -> microphone -> preamp.
If the source material is bright or brittle in sound, then a softer mic and mic pre with sufficient headroom will be suitable.
If the source material is soft, like a soft voice then a bright and clinical mic and mic pre will suffice.
If you add A-D converters into the chain then it's four things to get right in combination
Source material -> microphone -> preamp -> converter
I always find I can soften a sound in a mix using EQ or reverb, and sometimes compression, but it's harder to put crispness back on a dull sound. Hence my preference for brighter, cleaner, clinical mic preamps with inbuilt digital conversion. However, sometimes you can turn a great warm instrument into eardrum sandpaper using a crappy converter.
So think in terms of combinations. And convenience.