Yes, You are correct all the new MB only have one IDE connector limiting you to 2 IDE devices and you would have two buy a PCI /DE card for the other two. These cards run $14 and up.
You did not spell out / break out the IDE devices. IE 2 DVDRw drives, If so do you really need two. What number for HDD's 2, or 3. and what size. You may be able to purchase a single sata HDD that equals all of your HDD. Example a 500/650 Gig Asat HAD for $50 -> $60. Subtract the $15 that you will waste on the controller card and Your now only spending $35 -> $45 more and replacing old HDDs.
If you have two DVD drives then it does not make sense, as you could go to one Sata DVD drive for about $20 -> $25 dollars, ONLY $5 to $10 more than buying a Controller card.
There's an old saying, a penny saved is a penny earnd - But there is also that old saying penny wise, pound fullish. After you up grad that MB, you will at some point upgrade the DVD, and or HDD - Don't wast the money on the controller card unless it is the ONLY way (just can not squess the piggy bank) you can afford at the time.