doing a template for a web hosting site and i want to know what i need to shoot for

You're probably pretty safe keeping it in the 50-70 kb. range for most dial-up connections with a 30-40 kb. max download for inside pages (assuming common elements are cached).

I like to shoot for 20-30 kb., just to make sure I don't lose anyone, most notably the number of people in Asia/Pacific who only have 28.8 access, or the early technology adopters using PDA/cellphone browsing. But I'll take them up into a higher range every once in a while if I think it's safe enough.

Most hosting templates are probably much higher than this (150-300 range or more), but hosting templates are also well-known for their second-rate engineering. So if you're basing your own development efforts on those of common templates, you're probably not doing yourself many favors, except maybe (maybe) in the visual department.

My current site is about 90kb. Half that is my header image, which I'm planning on re-doing to decrease its size.

Hosting sites are kind of a special breed of site. Because the market is very saturated, you need to grab the user and prompt them to learn more about why you are the one they should choose.

The problem I have with most hosting site templates is that they almost all use Flash. Generally, 70-80% of those sites' total size is in a Flash animation that simply serves no purpose. You could easily do the same thing with images in half or less the size.

In my opinion, because of what I've said above, I think anything in the neighborhood of 100k or less is appropriate for a hosting site. Most sites will have many images (for instance, a spiffy header, image navigation buttons, plan boxes [which are generally images], etc.).

You can also significantly decrease your page size by using newer design techniques like XHTML and CSS, and eliminating tables from your design (except where appropriate). You can end up with a page half the size using CSS/XHTML vs HTML/Tables.