The best bang for your buck will be bi-metal blades. No thicker than your cutting you need a relatively high tooth count. Rule of thumb is that you always want a minimum of two teeth in contact with the piece being cut at all times. If you do a mix of thick and thin you can go for a varitooth design that will give the best of both a course and fine pitch tooth count in operation. Beyond that there are quite a few name brands that make quality blades, but not all make the exact same thing. Your best bet will be to do a little research and I'm sure you'll find a blade that will do all you want and then some, with a long life expectancy to boot.
As far as the guide bearings, every one I have ever seen is a standard needle bearing, or a standard cam type bearing. Any good bearing supply house ought to be able to get you replacements either with a bearing number, or by going by the measurements.
Hope this helps, and good luck.