Denise,
I was just catching up on last week's Histonet and saw your question about
heating slides for ISH.  Here's my two cents:
*Incubating Ovens are great for long (2-16Hr) Incubations at lower temps
(ie.37-42). If you are trying to denature the slide for just a few minutes
at 96 degrees, the incubating oven won't get your slides to temp as quick as
the following methods (plus if you only have 1 oven, then you have to reset
it to the hybridization temperature - which seems to take forever!)
*The heat block is great for small numbers of slides ~ 4 slides (although in
a pinch you can squeeze on 6)  I also take a top of a large pipette tip box
and make a temporary cover for the top
*I occasionally use a small vertical water bath with a coplin jar if I am
using a denaturing solution in addition to heat
*My current favorite is the Boekel Slide Moat (Fisher 05-450-31 $995).  This
is a great piece of equipment if you have more money than countertop space.
It holds about 30 slides which can be laid directly inside, a rubber gasket
with glass lid to keep it humid, comes up and down to temperature quickly
and maintains a constant temperature very well. It also only takes up about
1 1/2 square feet of counter space and is only about 6 inches high.  I'm
really sold on this piece of equipment!! :) Because of all the different
temperatures I needed in my experiments, I had 4 incubating ovens, 3
waterbaths, 2 heat blocks and absolutely no counterspace!  I'm now basically
using just the slide moat (I also turn the unit off and it doubles as a IHC
humidity chamber when I have too many slides for my regular immuno boxes)
O.K.  I'm done now!!!  Hope this helps!

Chris Rogahn
crogahn@prius.jnj.com