1. Hoshi.
Or is it Linda Park? I never bought into her ability to translate languages after hearing a sentence or two, but she's so sweet, so cute not only in appearance but also in attitudes; how could you hate her?
Very Ezri-like, I guess.
2. Phlox.
He's probably the most realistic character on the show: he has so many facets emanating from so few defining character traits... a lot like real people.
Written very well, acted excellently.
3. Shran.
Such an ego, but he pulls it off magnificently.
4. Soval.
Pretty good character growth, more complex than initially thought.
5. Degra.
He's never that likeable (willing to participate in genocide to save his kind from a vague distant unproven threat?), but he's a strong dramatic character nonetheless.
Other than the 2 examples mentionned, the main cast leaves me quite indifferent.
Unlike DS9 and Voyager, which had terrible characters (e.g. Sisko, Neelix) and great characters (e.g. Quark, Tuvok), ENT has a lot of "meh" characters.
ENT made me realise one thing: it's hard to care for a character unless s/he's fleshed out shortly after being introduced; by the time Reed, Tucker or Travis were fleshed out, it was too late for me to care.
Hell, in the first 3-4 episodes, I wasn't even sure if "Trip" and "Mr. Reed" were different characters or not. You don't recover from that.
Even Archer left me mostly indifferent.