I've used both types of adapters without problems. Sapphire is a cheap brand so this is a long shot, but check all the stuff that came with the video card in the box. The EVGA card I bought for a client's build came with an HDMI to VGA adapter. HDMI to DVI is easier since they're both digital - bought mine for a couple bucks from Monoprice. HDMI to VGA is digital to analog, so those are a bit tougher to find. Both are fairly small and cheap. You only need a big converter box if you also need to split out the audio signal that HDMI can carry (the video is uncompressed, but the audio can be compressed so the box is needed to uncompress it before converting it to analog).
The only gotcha I can think of is that HDMI supports HDCP while DVI and VGA don't. So if you try to watch some blu-ray movies on your computer/monitor that's not using HDMI to HDMI, the player may dither the image down to 480p. So you'd have to first rip the movie and convert it to a non-protected video format in order to view it at 1080p. (Yes, Hollywood's anti-piracy measure actually forces you to take the first step in pirating. Rip blu-rays to view them at full resolution, at which point you have a nice juicy unprotected video file you can share with your friends.)