I've not figured out if this is possible. If I want to move several items (that aren't in a group) is there a way to simply lasso them in Hammer to select them all? Going around with the selection tool manually is painful...

I believe holding down ctrl (maybe shift?) allows for multiple selection. There's no lasso, but you can select more than one object that way.

I think thats what he's doing.
Deselect everything, and click and drag a square. It'll make a yellow-dashed box in that view. If you press enter, it'll select everything in that square from that view, so if you try and select a room from top view, it'll select everything below it as well. You can then go into the side and front views to fine tune your selection and drag it to fit just what you want. It selects everything inside and touching, so you may still have to go deselect some objects with ctrl-click.

I use ctrl a lot, selecting selection tool, then moving mouse over the 3d wiev, pressing Z, then I just move around with mouse and keys wasd and while holding ctrl selecting items. Just cant click too fast or it will be a doubleclick.
I use 3d viwe to select thing mor than the 2d views.

That worked, thanks a lot Interitus! Geez, I wish I knew that little factoid a while ago...

Thanks.

Man you would not belive how many faces i applied nodraw to until I found of the magical Ctrl Button. It saved me so much time, Also you can select multiple textures or faces as well, just like objects doing the same thing.

also, if you're selecting a room and its got a lot of models, or models that stick out past the walls of your room, its a good idea to put everything in a brush that sticks out past all models and is aligned to a grid of 32 or 64. Doesnt really matter what texture, but I apply the "skip" texture to it cause its see thru and if I forget to delete it after moving its ignored compiling.

This keeps your brushes from being off the grid when you move everything. I've moved my elevators, and all my brushes have been just a tiny bit off a 1 grid. This causes noticeable graphic glitches, and can cause errors with vbsp and such.

Yeah, this only happens if you place props or objects randomly, and dont align the first time, as when they are all selected, they cause everything to shift un-evenly.

What about for entities that have odd sizes, like the cube of 40.5? They always seem to be a little off the grid lines.

And what are those purple spheres that seem to get into a funny position when you move. From what I've gleaned they're called helpers. But what do they do? (I discovered this when it create a leak because the helper had moved outside my map into the void.)

The origin of a props also defines their "center", where they are auto-snapped to the grid - a good example being the button base and button top, or the 3D skybox citadel models. When you group select objects, these auto-centers are ignored and instead the nearest edge of the bounding box (I think?) is how things are selected. So if you have a room with a piece of a prop sticking into the void, and you grab the selection near that piece, everything will be snapped to that corner - and thus making everything off of the normal grid lines.

In my experience, moving a selection of objects that includes at least one brush will favor keeping the brush aligned to the grid as opposed to other objects.

This comes in handy if you need to align a bunch of objects very precisely (say, at a grid size of 2 or 4) and then you want to move the whole 'cluster' of objects at a larger grid size (say, 32 or 64). If there's at least one brush, a brush will be aligned to the grid and the point entities will move relative to it.