I can't be certain but the SATA type should give you faster performance as SATA is a newer type of connection to IDE, also you are better using the 200GB one as its better to have more space than you need than not enough. You are limited to what type of hard drive connection you can use by your motherboard, so you would need to look on your motherboard to determine what type of connection can be used.
WRT the disk capacity affecting performance, it would depend on a variety of factors:
- The size (diameter) of the disk platter - The number of disk platters (physical recording surfaces) - The seek speed (i.e. how long it takes for the heads to move in and out across the disk) - The rotational speed.
If all the above were equal, common sense suggests that bigger capacity is better in that the data must be more compressed and therefore on a defragmented disk with all the files are substantially grouped together the seek times would be lower as the physical distance needed to move across the platter is less.
Having said all that, SATA should be faster than IDE and a higher rotational speed should (must?) be faster and these might be considered the deciding factors. Other than that, check the specific specs of the drives concerned.