SDTV is either 576i or 480i (PAL & NTSC - not including any hybrids)
576i is NOT a standard! It is called PAL. I does use an interlaced set of 576 lines. Don't know about the NTSC/480i - my exams only covered UK standards, so I would need to check. I doubt NTSC SD is called 480i, as that would confuse with the 'HD' standard 480i, but as I say, I would need to check for def.
480i was defined in the first lot of HD specs despite being lower than what us PAL users are used to. Crazy.
In this country, I don't think we'll ever get DTT 1080p due to bandwidth constraints. For many, 1080i is as good for broadcast. Local content (DVDs, photos, Games consoles etc) will look better with the extra detail in 1080p.
BRD has got the sexier name, but really requires PS3 to be success to compete effectively against HD-DVD which has Microsoft/Intel backing (PCs are where such tech gets defined now). HD-DVD also has more titles (though less distributers) currently. The likes of BBC only mention BRD when talking HD, so may help a little.