I am trying to figure out which tags and readers are the state-of-the-art options.
I don't believe there is a "gold standard," per se. Both the ISO 14443 and ISO 15693 standards are well established, and products based on those standards work well and are interoperable. ISO 14443 is a short-range standard designed for smart-card transactions, while ISO 15693, intended for proximity cards, is used for access control and inventory monitoring.
Feig Electronic, IDTronic, Magellan Technology, Proxima RF, Secura Key, SkyeTek, Tagsys RFID and other companies sell RFID interrogators. NXP Semiconductors, Texas Instruments and others manufacture chips used in high-frequency (HF) transponders.
Perhaps the best way to choose a vendor is to do so based on your company's particular needs. NXP produces Mifare chips with encryption to protect sensitive data. And Magellan has developed what it calls Phased Jitter Modulation (PJM), enabling its readers to interrogate multiple tags in close proximity to one another. Similarly, tags are available in many different form factors, and choosing a company that offers the design you're looking for is important.
—Mark Roberti, Founder and Editor, RFID Journal