If the Hitachi Travelstar drives still hold up as well as these did some years ago than that could be one way to go. I've some experience with these drives and have not found much to complain about. My first was a 40gb 4200rpm with 2mb buffer (forgotten the model number). A good and reliable drive despite a lot of use in at least 6 days in every week. I finally upgraded because I needed more storage but also because I wanted a faster drive. I went for the Travelstar 7k100 with Ide interface, which my laptop had. I also had a look at Seagate, I think it was, and their equivalent 2.5" Momentus 100gb, 7200rpm with 8mb cache but the Hitachi had better read/write performance according to tests if my memory serves me correct, so I went for the Hitachi.
My Hitachi 7k100 is still doing a good job after having seen daily use in first an other laptop which I used every day. It is now sitting in an old laptop which run a gameBot 24/7 and the drive never seems to spin down as it makes a slight ticking noise sometimes. Still working well. I've another Hitachi 7k100 though with Sata interface in an other Core 2 Duo based laptop. Probably the stock drive I would assume as I'm the second owner of that laptop. I'm not using that laptop much but it works whenever I want to use it.
My experience with these older Hitachis is that the general performance was good for the time being and reliability as well.
Edit: Oops. I now see that you are looking for a 3.5" drive. I was thinking about 2.5" as you mentioned the Macbook.