No, you could buy an internal IDE, SCSI, or SATA card. You
could still buy an external (USB or firewire) enclosure
instead, which makes it transportable and removable, but
they're far slower than modern internal controllers.
If you have a spare PCI slot, I'd get a PCI card (since you
mention no specific need for external(ness)), either SATA or
IDE depending on which type of drives you want. Your next
system will probably have SATA built-in but PATA (IDE) too,
so it's your call... PATA drives are still a little cheaper
but the cards themselves are nearly same prices on average.
A good place to get them is on Ebay. I bash Ebay and am not that crazy
about buying things there as Ive wasted way too much time in the past
trying to get things only to see them jump close to retail price at
the end but one of the few things they seem to have OK prices on are
little things for PCs like controller cards, sata converters etc.
Even pricewatch I dont know if many stores are avoiding them now but
they dont seem to show very good prices nowadays. Its better to just
search Newegg , Monarch and ZZF yourself though its worth one search I
guess if you are looking for something just to make sure.
With ebay for instance they show controller cards for $8 but the
shipping is like 8 bucks so it inevitably comes out around 15 bucks or
so usually.
Monoprice.com is also well known for knickknacks for PCs at a
rockbottom price. They used to sell on ebay maybe they still do. Thats
how I ended up buying the converters and DVI cable there and they had
incredible prices and ship USPS which is important for me and gave me
decent service. Everyone points out they have great prices on various
cables. Cant remember if they sell controller cards though. Its
possible newegg etc may have one for cheap with cheap shipping that
might come out cheaper than Ebay.