DI - Cause I don't have enough mics.

(That said, I only have 3 channels of DI so the rest are just adapters.)

Short answer: It depends.
Venue size? Stage size?

Generally I prefer close mic'd amps to DI. If it's really crowded up there and I'm worried about mics/stands getting kicked, and the amp has a good sounding DI out, I'll do that.
Almost always DI for the bass. Again, if the amp DI sounds good, I may take that instead of a DI from the instrument.

Smaller venue? I let the stage do most of the work, and add in only as necessary (vox, reinforcement of guitars, etc).

I just think most DIs sound a little sterile and lifeless - like the sound was created in a reverb-less vacuum chamber in a lab. Especially w/ guitars.

Sorry, I missed the guitar amp part of the question on your other thread. I mic the guitar amps. Mic selection and placement vary a little depending on style of music, what other instruments are on-stage, how close together they are. Once in a while I'll run across someone with a good sounding pre-amp / processor and take the direct feed at their request. But generally, mic is the way to go for guitar amps.

And again, for bass it depends on how good the bass amp sounds on-stage. If it's a mediocre to bad bass rig, I'd almost always just run the bass guitar into DI ahead of the bass amp.
If it's a great sounding live bass rig, and I can spare the channel, I might do both the DI and a good mic. And I'd mix them at the board to heavily favor the mic. If I could only spare one channel with a great sound bass amp, I'd prefer a mic - but DI (with a ground-lift) is nearly foolproof.

The mic should have more warmth and body, while the DI will give you a cleaner, tighter, brighter sound with more of the attack (especially if they play with a pick). The DI may be relatively 'sterile', but still nothing you can't overcome at the board.

But here's the thing... in a smallish venue, there's often plenty of bass coming from the stage anyway, and all I need to amplify is the mids & highs to put some definition back in the notes that are booming all through the room.

Thanks for extrapolating/clarifying some of my suggestions, Hawk.

Here's where I differ a little...

You've got to know and trust the bassist/rig to rely solely on a mic, IMO. As a bassist, if a player's got a good rig, it will show in the room. If I mic a bass amp (as an engineer), I want to capture it w/ a little space.
If the venue doesn't allow for that (I gotta have some kind of DI on bass), then no mic.

Don't get me wrong - I love to add a little bump from the amp if possible. It's just that close mic'd bass amps *typically* don't add much more than flub. There's usually enough of that in the room unless it's a really big space.
I guess I'm just not a fan of reinforcing bass (esp in smaller spaces) unless you're able to use the mic to also add some punch and presence.
Could just be the bassists/rigs I've happened to mic?

Guitars are different. W/ the right mic in the right place, I gotta have that amp sound in the house. Again, for reinforcement purposes.

I offer some different perspectives, knowing your live experience far exceeds mine. Thrown into the fire, I'd probably take your suggestions over mine.

Great, thanks for the input. Ill take everything into account and play around with setups a little more