Another thing that can bog down the modeling panels is smooth preview being used on a lot of objects.

Also if your scene is getting complex and you don't feel like making display layers for everything then you can use this script I made. It works on components as well as objects. You can put it on a shelf or make a hotkey or whatever. I went the hotkey route.

//----------------------------------------------

{

//--get panel that has focus.
string $currentPanel = `getPanel -wf`;

//--if none available, get panel under mouse pointer.
if ($currentPanel == "")
$currentPanel = `getPanel -up`;

//--make sure panel is a modeling panel.
string $panelType = `getPanel -to $currentPanel`;

//--if so, carry on.
if ($panelType == "modelPanel"){

//--query if isolation is active.
int $isolateCheck = `isolateSelect -q -state $currentPanel`;

//--if its on, turn it off pweez :3.
if ($isolateCheck == 1){
isolateSelect -state 0 $currentPanel;
//--if not, turn it on.
}else{
enableIsolateSelect $currentPanel 1;
isoSelectAutoAddNewObjs $currentPanel 1;
isolateSelect -state 1 $currentPanel;
isolateSelect -update $currentPanel;
}
}

}

//--------------------------------------------------------------