I might as well say what roguelikes i have tried and what i thought of them.
DoomRL: My first and favourite roguelike (i found out about this because i thought it'd be silly if a game was both in the "doomclone" and "roguelike" genres). The level generator is vastly superior to most other roguelikes i've tried, your deaths are almost never out of nowhere (kehehe levels can be an exception), and there is such a variety to challenge you can use. I also like that there are unlocks, but they are light (can be achieved in under 10 games). Advanced assemblies can be annoying (mostly just because you can't test through possible assemblies like you can with the basic assemblies). Achievements set a nice standard for evaluating how challenging certain combinations are (Ultra Violent vs Angel of ____ on HMP).
Brogue: This is my second favourite, i love both the graphical style and the fantastic level generator. Although the genre is light on exploration as a theme, this game has done the best at keeping some sorta exploratory feel for the longest, before wearing down, mostly because it was well put together and because the levels change in style as you go deeper. I've had trouble getting use to the game's mechanics, however, as i am terribly bad at brogue.
Tome4: This is a roguelike i play a fair amount despite numberous problems with it. What makes the game so interesting is the vast number of very well thought out and very interesting classes. This makes learning the game just so you can learn these classes and get to try them seem worth the effort. The removal of consumables is great for a game with regenerating health, and the lore is fairly well writen and interesting.
However, the game requires such an investment with any given character, and deaths are rarely easy to determine the cause of. Parts of the game that are essentually vital to playing start off locked, and some classes got vastly more attention than others (either because of bugs like my favourite class, the paradox mage, or because of the creator's favoritism like archmage). The community on the live chat that tome4 is so proud of is almost MOBA level bad. Also, doing well requires you to know a lot of underexplained ideas, which really add up to frustration if you don't get outside help (and figuring them out is about as rewarding as learning a keybinding by trial and error). Also, this game can't really decide whether it works like angband (lots of points into everything) or more like DoomRL/Diablo (skill trees split the class into various 'sub-classes')
All and all, great ideas, interesting game, execution needs work.
Gearhead: I have difficulty getting this to work or knowing what to do. Haven't taken a closer look at it.
Steamband: I want to like this game, it is very flavorful, and the setting works well with general item based pseudomagic and miracle tonics of unknown effect. But i don't have the patience for an Angband variant's interface. I have gotten further here than in hengband though.
Hengband: Like steamband except i am less intersted in it. My friend's favourite roguelike, but i havn't gotten very far, though i havn't tried as hard as i could have.
Powder: The style of game assumes you pick up and play with the normal character lasting 5 minutes, and a successful one lasting 15. Apparently a lot of players like this style, i am not one of them.
RoguePlanet: if the levels were shorter, this would be fun pick up and play maze game, but they drag on too long killing much of the appeal.
Desktop Dungeons: I have played a lot of this, very fun roguelike if you like math (math the roguelike is an accurate description). Gameplay revolves around figuring out what combination allows you to kill the most out of level monster possible. The game feels in practice more like minesweeper than a roguelike. However, i don't think i'd consider paying more than $5 for it, and they now want to charge $15 for it, so i don't care about the game anymore.
Spelunky: This is the other game with a vaguely exploratory feel to it initially. Fun adventure platformer, not really a roguelike outside of the randomly generated levels (and random maps don't seem special to strategy game players, as civilization, Age of Empires, and Sim City 2000 each use one).
The Binding of Issac: Pretty fun action game, like the zelda 1 dungeons randomly generated.
Dungeons of Dreadmore: I was really bored with this game after briefly playing it. Also, the mouse controls being manditory was rather annoying. I'm not willing to say it is not worth the $2 i paid for it as i will probably try it again later, but there isn't really a good hook to the game that i can see.