A Solid State Drive (SSD) offers the best balance between speed, capacity, and value for most users. Unlike Hard Disk Drives (HDDs) which use spinning disks to read and write data, SSDs contain no moving parts and therefore are able to access data faster, are smaller, lighter, and usually more durable. Though they can be more expensive than HDDs, the performance benefits often justify the cost, making them an excellent choice for a system upgrade when looking for enhanced speed and reliability without excessively high costs. SCSI and IDE are older interfaces for hard drives, not types of drives themselves, which means they are not directly related to the balance of speed, capacity, and value that the question asks about. An optical drive is primarily used to read from and write to CDs, DVDs, and Blu-ray Discs, and is not suitable for the purpose of internal file storage upgrade considering capacity and speed requirements.