I mainly use accesstoinsight.org and suttacentral.net. Another good source is themindingcentre.org. For the Dhammapada, tipitaka.net is good. A new website is dhammatalks.org.
SuttaCentral has more suttas translated to English compared to any other source, as far as I can see. You can find many uncommon suttas translated.
Both SuttaCentral and AccessToInsight have multiple translations from various translators.
Ven. Sujato's translations are completely on SuttaCentral, but you can also find alternative translations from other translators like Ven. Bodhi, Ven Thanissaro, Ven. Anandajoti etc.
SuttaCentral also has inline Pali with English translations for Ven Sujato's translations - this is the best source to compare Pali sentences with their English translation counterparts. There's also a Pali-English dictionary on the site.
One drawback is that there are no commentaries on SuttaCentral together with the sutta translation, but you may find this indirectly on their discussion site.
AccessToInsight and dhammatalks
AccessToInsight has Ven Thanissaro and other translators like Ven. Nanamoli, Ven. Buddharakkhita, Ven. Anandajoti, Ven. Bodhi, I.B. Horner, Rhys Davids etc. Some sutta translations here have short commentaries either at the top or on the footnotes.
AccessToInsight also has a very nice glossary.
The nice thing about AccessToInsight is that I can search it using Google's "site:" prefix.
Recently, I noticed that there is a new site hosting Ven. Thanissaro's translations - dhammatalks.org.
The Minding Centre
The Minding Centre's Dhammafarers / Sutta Discovery series has translations and commentaries by Piya Tan. These are pretty good. They are in PDF format.
The Minding Centre is a very good source of commentaries. Piya Tan also refers to the traditional commentaries in his research. His research is pretty good.
For Dhammapada, you can find translations on AccessToInsight and SuttaCentral, but you won't find the stories of each Dhammapada verse that come from the traditional commentaries.
For Dhammapada stories, tipitaka.net is the best source.
You can also search tipitaka.net using Google's "site:" prefix.
Whose translation is the best?
I tend to use Ven. Bodhi, Ven. Sujato, Ven. Thanissaro and Piya Tan as my preferred translations.
Of these, I usually find Ven. Bodhi using English terms in the most natural way to capture and convey the meaning of Pali sentences. This would be my first choice.
Ven. Sujato tends to be as direct as possible with his choice of words - trying to be word-for-word accurate. This would be my second choice.
Meanwhile Ven. Thanissaro tends to be grand (e.g. using "Lord") and using unusual translations, but they still convey the intended meaning.
Ven. Thanissaro and Piya Tan tie for third place in my opinion.
Below is a list of ten unusual English translations by Ven. Thanissaro, compared to Ven. Bodhi or Ven. Sujato. Ven. Thanissaro tends to use unusual or strange or archaic English words or phrases.
- "Lord" instead of "venerable sir" (Bodhi) or "sir" (Sujato) for "bhante" (e.g. MN 147)
- "Stress" instead of "suffering" for "dukkha" (e.g. MN 146)
- "Inconstant" instead of "impermanent" for "anicca" (e.g. MN 146)
- "uninstructed run-of-the-mill person" instead of "untaught ordinary person" (e.g. MN 1)
- "Right discernment" instead of "right wisdom" for "sammappañña" (e.g. MN 146)
- "Gnosis" instead of "final knowledge" (Bodhi) or "enlightenment" (Sujato) for I think "aññārādhanā" (e.g. MN 70)
- Translating proper nouns like "LongNails" instead of just stating the original "Dīghanakha" (in MN 74) - this is a person's name
- "Unbinding" instead of "Nibbāna" (Bodhi) (e.g. MN 75). Ven. Sujato uses "extinguishment" here which is slightly better than "Unbinding" - this is a well-known technical term that need not be translated.
- "Worthy One" instead "Arahant" (Bodhi) (e.g. MN 1). Ven. Sujato uses "perfected" here which is better. This is a well known technical term that need not be translated.
- "Seized" instead of "obsessed" for I think "pariyuṭṭhaṭṭhāyī" (e.g. SN 22.1)
For an example of a longer phrase - from MN 19:
- "his mind is bent by that thinking imbued with sensuality" (Thanissaro)
- "his mind inclines to thoughts of sensual desire" (Bodhi)
- "Their mind inclines to sensual thoughts" (Sujato)
You can see Ven. Thanissaro's strange use of "bent" instead of "inclines" above. There are many such examples of strange translations.
Sometimes, Ven. Thanissaro has better translations e.g. "fabrications" instead of "volitional formations" (Bodhi) or "choices" (Sujato) e.g. SN 22.1. But usually it's the other way round.
Rarely, most of them get it completely wrong e.g. viññāṇaṃ anidassanaṃ - see this question. Here, it was translated as "invisible consciousness" (Sujato) or "consciousness without surface" (Thanissaro). Actually it should be "that which can be known or cognized" i.e. Nibbāna.