IE7 doesn't understand the * html hack as that only targets IE6. You can use the *+ html hack for IE7.
There is rarely a difference in padding, margins and font-size in IE7 (excluding known bugs) so you would seldom need to hack those. Most IE7 bugs/behaviours can be catered for by doing things in a structured way from the start and avoiding the need to hack. If you make sure that what you are telling the browser to do is correct then you can avoid it error handling (such as when dimensions are over constrained and the browser has to error handle code that doesn't make sense).
Make sure floats are contained and that margins are applied correctly by taking into account margin collapse behaviour. Don't apply top margin top elements following floats and remember that IE7 will auto contain child floats when it is in haslayout mode so just make sure other browsers have the floats contained also and then they will all agree.
If you have parent elements holding complicated content then make sure the element is in haslayout mode for IE7 otherwise the children may be misplaced. For example if you use a parent with position:relative as a stacking context for absolute child element then the parent will need to be in haslayout mode (see css faq on haslayout).
Following a few simple rules will avoid the need for many IE hacks. Only use a hack when its a known bug and not just because something doesn't fit.
So my question is if I'm not using any hacks but html* should I be worried? Is there anything that you think I could be missing or is it pretty much the same for the rest of you?
If there is potential need for hacks for Safari, Chrome, Opera etc, I would love to know what sort of things to look out for.
I appreciate your advice.
Leave other browsers alone. If you run into a specific bug then its better to code around it with a change of design. There are the odd times that a hack would come in handy but its a slippery slope and its best not to paint yourself into that corner