I'm currently running a pair of 1gb Kinston DDR400 dimms on the older Socket A here running Steam and other large apps without issues. Corsair's ValueSelect also gets some rave reviews. I do favor Kingston over Corsair on Asus models boards however. The make and model was left out of your sig. Matching same sized dimms usually helps since the majority of new boards are dual channel.
Well, I didn't really think of looking at the stick itself maybe I could. hehe. I know it is pc133 as far as the link shows you but hld on a sec...... It is a compaq 5412rsh. Don't know if that helps but it is 168-pin?? Max bandwith is 133mhz. O now here we go. Manufacturer is micron technology.
You would have to run a very extensive search if not find a vendor that specializes in carry all types of memory. The oldest memory currently seen at the bulk of online vendors would be PC2100 for Socket A boards they still carry until those are gone. DDR400 and up is the continuing trend. It seems like an updated system would get much further at this time.
The main difference with the different DDR types is the operating frequency. Buying a brand and type of memory with faster timings helps with gaming. But now you would be looking at a new build there. For getting memory now for the 168pin simms run there have a look at http://www.4allmemory.com/index.cfm?fuseaction=search.memorySearch&manufacturer_id=25&model_id=-1040 Of course they specialize in memory.
One old Shuttle board here took three 256mb PC133 modules to max it out just like the model you have there. But you can also step that up a little as well. "System Memory 256MB 133 MHz SyncDRAM, 3 Total DIMM Slots Upgradeable to 1.5GB (SyncDRAM DIMM required)" according to the specifications seen at http://h10025.www1.hp.com/ewfrf/wc/...docname=c00009505&lc=en&jumpid=reg_R1002_USEN
Since newegg is carrying this type of memory where many are not or selling at a higher price like the other site why not? That will go on your board easy enough. They should even have the SDram available for the 1.5gb capacity your board supports using that type. It would certainly cost a few buck more. But it would boost the overall system there. Eventually you will want to go into something newer however. If you are on a tight budget the memory there should see good results. Get it while they still carry it however. After so many years many places simply won't carry memory for the older boards.